diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4d0a99b2c..4a805715c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@ Find out more about isort's release policy [here](https://pycqa.github.io/isort/
   - Fixed #1631: as import comments can in some cases be duplicated.
   - Fixed #1667: extra newline added with float-to-top, after skip, in some cases.
   - Fixed #1594: incorrect placement of noqa comments with multiple from imports.
+  - Fixed #1566: in some cases different length limits for dos based line endings.
   - Implemented #1648: Export MyPY type hints.
   - Implemented #1641: Identified import statements now return runnable code.
   - Implemented #1661: Added "wemake" profile.
diff --git a/isort/output.py b/isort/output.py
index 13f72a3d5..61c2e30ec 100644
--- a/isort/output.py
+++ b/isort/output.py
@@ -504,7 +504,13 @@ def _with_from_imports(
                             config=config,
                             multi_line_output=wrap.Modes.VERTICAL_GRID,  # type: ignore
                         )
-                        if max(len(x) for x in import_statement.split("\n")) > config.line_length:
+                        if (
+                            max(
+                                len(import_line)
+                                for import_line in import_statement.split(parsed.line_separator)
+                            )
+                            > config.line_length
+                        ):
                             import_statement = other_import_statement
                 if not do_multiline_reformat and len(import_statement) > config.line_length:
                     import_statement = wrap.line(import_statement, parsed.line_separator, config)
diff --git a/tests/unit/test_regressions.py b/tests/unit/test_regressions.py
index 9f1755254..26517598c 100644
--- a/tests/unit/test_regressions.py
+++ b/tests/unit/test_regressions.py
@@ -1607,3 +1607,15 @@ def test_isort_shouldnt_move_noqa_comment_issue_1594():
 )
 """
     )
+
+
+def test_isort_correctly_handles_unix_vs_linux_newlines_issue_1566():
+    import_statement = (
+        "from impacket.smb3structs import (\n"
+        "SMB2_CREATE, SMB2_FLAGS_DFS_OPERATIONS, SMB2_IL_IMPERSONATION, "
+        "SMB2_OPLOCK_LEVEL_NONE, SMB2Create,"
+        "\nSMB2Create_Response, SMB2Packet)\n"
+    )
+    assert isort.code(import_statement, line_length=120) == isort.code(
+        import_statement.replace("\n", "\r\n"), line_length=120
+    ).replace("\r\n", "\n")