diff --git a/packages/babel-parser/src/plugins/flow.js b/packages/babel-parser/src/plugins/flow.js
index 5e7187455da2..ab5f646b6efb 100644
--- a/packages/babel-parser/src/plugins/flow.js
+++ b/packages/babel-parser/src/plugins/flow.js
@@ -2061,6 +2061,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
           return node.operator === "=";
 
         case "ParenthesizedExpression":
+        case "TypeCastExpression":
           return this.isAssignable(node.expression);
 
         case "MemberExpression":
diff --git a/packages/babel-parser/test/fixtures/flow/regression/arrow-in-ternary-with-param-type-and-return-type-like/input.js b/packages/babel-parser/test/fixtures/flow/regression/arrow-in-ternary-with-param-type-and-return-type-like/input.js
new file mode 100644
index 000000000000..1f0c3e33482c
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/regression/arrow-in-ternary-with-param-type-and-return-type-like/input.js
@@ -0,0 +1,2 @@
+test
+  ? (x: T): U => y
diff --git a/packages/babel-parser/test/fixtures/flow/regression/arrow-in-ternary-with-param-type-and-return-type-like/output.json b/packages/babel-parser/test/fixtures/flow/regression/arrow-in-ternary-with-param-type-and-return-type-like/output.json
new file mode 100644
index 000000000000..3c80e21673a6
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/regression/arrow-in-ternary-with-param-type-and-return-type-like/output.json
@@ -0,0 +1,220 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 23,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 2,
+      "column": 18
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 23,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 2,
+        "column": 18
+      }
+    },
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start": 0,
+        "end": 23,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 2,
+            "column": 18
+          }
+        },
+        "expression": {
+          "type": "ConditionalExpression",
+          "start": 0,
+          "end": 23,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 0
+            },
+            "end": {
+              "line": 2,
+              "column": 18
+            }
+          },
+          "test": {
+            "type": "Identifier",
+            "start": 0,
+            "end": 4,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 0
+              },
+              "end": {
+                "line": 1,
+                "column": 4
+              },
+              "identifierName": "test"
+            },
+            "name": "test"
+          },
+          "consequent": {
+            "type": "TypeCastExpression",
+            "start": 10,
+            "end": 14,
+            "loc": {
+              "start": {
+                "line": 2,
+                "column": 5
+              },
+              "end": {
+                "line": 2,
+                "column": 9
+              }
+            },
+            "expression": {
+              "type": "Identifier",
+              "start": 10,
+              "end": 11,
+              "loc": {
+                "start": {
+                  "line": 2,
+                  "column": 5
+                },
+                "end": {
+                  "line": 2,
+                  "column": 6
+                },
+                "identifierName": "x"
+              },
+              "name": "x"
+            },
+            "typeAnnotation": {
+              "type": "TypeAnnotation",
+              "start": 11,
+              "end": 14,
+              "loc": {
+                "start": {
+                  "line": 2,
+                  "column": 6
+                },
+                "end": {
+                  "line": 2,
+                  "column": 9
+                }
+              },
+              "typeAnnotation": {
+                "type": "GenericTypeAnnotation",
+                "start": 13,
+                "end": 14,
+                "loc": {
+                  "start": {
+                    "line": 2,
+                    "column": 8
+                  },
+                  "end": {
+                    "line": 2,
+                    "column": 9
+                  }
+                },
+                "typeParameters": null,
+                "id": {
+                  "type": "Identifier",
+                  "start": 13,
+                  "end": 14,
+                  "loc": {
+                    "start": {
+                      "line": 2,
+                      "column": 8
+                    },
+                    "end": {
+                      "line": 2,
+                      "column": 9
+                    },
+                    "identifierName": "T"
+                  },
+                  "name": "T"
+                }
+              }
+            },
+            "extra": {
+              "parenthesized": true,
+              "parenStart": 9
+            }
+          },
+          "alternate": {
+            "type": "ArrowFunctionExpression",
+            "start": 17,
+            "end": 23,
+            "loc": {
+              "start": {
+                "line": 2,
+                "column": 12
+              },
+              "end": {
+                "line": 2,
+                "column": 18
+              }
+            },
+            "id": null,
+            "generator": false,
+            "async": false,
+            "params": [
+              {
+                "type": "Identifier",
+                "start": 17,
+                "end": 18,
+                "loc": {
+                  "start": {
+                    "line": 2,
+                    "column": 12
+                  },
+                  "end": {
+                    "line": 2,
+                    "column": 13
+                  },
+                  "identifierName": "U"
+                },
+                "name": "U"
+              }
+            ],
+            "body": {
+              "type": "Identifier",
+              "start": 22,
+              "end": 23,
+              "loc": {
+                "start": {
+                  "line": 2,
+                  "column": 17
+                },
+                "end": {
+                  "line": 2,
+                  "column": 18
+                },
+                "identifierName": "y"
+              },
+              "name": "y"
+            }
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/flow/regression/arrow-in-ternary-with-param-type-and-return-type/input.js b/packages/babel-parser/test/fixtures/flow/regression/arrow-in-ternary-with-param-type-and-return-type/input.js
new file mode 100644
index 000000000000..a36f5ca0c5d8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/regression/arrow-in-ternary-with-param-type-and-return-type/input.js
@@ -0,0 +1,3 @@
+test
+  ? (x: T): U => y
+  : z
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/flow/regression/arrow-in-ternary-with-param-type-and-return-type/output.json b/packages/babel-parser/test/fixtures/flow/regression/arrow-in-ternary-with-param-type-and-return-type/output.json
new file mode 100644
index 000000000000..6be59ef645aa
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/regression/arrow-in-ternary-with-param-type-and-return-type/output.json
@@ -0,0 +1,250 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 29,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 3,
+      "column": 5
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 29,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 3,
+        "column": 5
+      }
+    },
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start": 0,
+        "end": 29,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 3,
+            "column": 5
+          }
+        },
+        "expression": {
+          "type": "ConditionalExpression",
+          "start": 0,
+          "end": 29,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 0
+            },
+            "end": {
+              "line": 3,
+              "column": 5
+            }
+          },
+          "test": {
+            "type": "Identifier",
+            "start": 0,
+            "end": 4,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 0
+              },
+              "end": {
+                "line": 1,
+                "column": 4
+              },
+              "identifierName": "test"
+            },
+            "name": "test"
+          },
+          "consequent": {
+            "type": "ArrowFunctionExpression",
+            "start": 9,
+            "end": 23,
+            "loc": {
+              "start": {
+                "line": 2,
+                "column": 4
+              },
+              "end": {
+                "line": 2,
+                "column": 18
+              }
+            },
+            "predicate": null,
+            "returnType": {
+              "type": "TypeAnnotation",
+              "start": 15,
+              "end": 18,
+              "loc": {
+                "start": {
+                  "line": 2,
+                  "column": 10
+                },
+                "end": {
+                  "line": 2,
+                  "column": 13
+                }
+              },
+              "typeAnnotation": {
+                "type": "GenericTypeAnnotation",
+                "start": 17,
+                "end": 18,
+                "loc": {
+                  "start": {
+                    "line": 2,
+                    "column": 12
+                  },
+                  "end": {
+                    "line": 2,
+                    "column": 13
+                  }
+                },
+                "typeParameters": null,
+                "id": {
+                  "type": "Identifier",
+                  "start": 17,
+                  "end": 18,
+                  "loc": {
+                    "start": {
+                      "line": 2,
+                      "column": 12
+                    },
+                    "end": {
+                      "line": 2,
+                      "column": 13
+                    },
+                    "identifierName": "U"
+                  },
+                  "name": "U"
+                }
+              }
+            },
+            "id": null,
+            "generator": false,
+            "async": false,
+            "params": [
+              {
+                "type": "Identifier",
+                "start": 10,
+                "end": 14,
+                "loc": {
+                  "start": {
+                    "line": 2,
+                    "column": 5
+                  },
+                  "end": {
+                    "line": 2,
+                    "column": 9
+                  },
+                  "identifierName": "x"
+                },
+                "name": "x",
+                "typeAnnotation": {
+                  "type": "TypeAnnotation",
+                  "start": 11,
+                  "end": 14,
+                  "loc": {
+                    "start": {
+                      "line": 2,
+                      "column": 6
+                    },
+                    "end": {
+                      "line": 2,
+                      "column": 9
+                    }
+                  },
+                  "typeAnnotation": {
+                    "type": "GenericTypeAnnotation",
+                    "start": 13,
+                    "end": 14,
+                    "loc": {
+                      "start": {
+                        "line": 2,
+                        "column": 8
+                      },
+                      "end": {
+                        "line": 2,
+                        "column": 9
+                      }
+                    },
+                    "typeParameters": null,
+                    "id": {
+                      "type": "Identifier",
+                      "start": 13,
+                      "end": 14,
+                      "loc": {
+                        "start": {
+                          "line": 2,
+                          "column": 8
+                        },
+                        "end": {
+                          "line": 2,
+                          "column": 9
+                        },
+                        "identifierName": "T"
+                      },
+                      "name": "T"
+                    }
+                  }
+                }
+              }
+            ],
+            "body": {
+              "type": "Identifier",
+              "start": 22,
+              "end": 23,
+              "loc": {
+                "start": {
+                  "line": 2,
+                  "column": 17
+                },
+                "end": {
+                  "line": 2,
+                  "column": 18
+                },
+                "identifierName": "y"
+              },
+              "name": "y"
+            }
+          },
+          "alternate": {
+            "type": "Identifier",
+            "start": 28,
+            "end": 29,
+            "loc": {
+              "start": {
+                "line": 3,
+                "column": 4
+              },
+              "end": {
+                "line": 3,
+                "column": 5
+              },
+              "identifierName": "z"
+            },
+            "name": "z"
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file