diff --git a/dns/edns.py b/dns/edns.py
index ef79b5f0..af90827a 100644
--- a/dns/edns.py
+++ b/dns/edns.py
@@ -455,7 +455,7 @@ def to_text(self) -> str:
             server = binascii.hexlify(self.server).decode()
         else:
             server = ""
-        return f"COOKIE {client}:{server}"
+        return f"COOKIE {client}{server}"
 
     @classmethod
     def from_wire_parser(
diff --git a/tests/test_edns.py b/tests/test_edns.py
index 8e63b21d..74b16c5c 100644
--- a/tests/test_edns.py
+++ b/tests/test_edns.py
@@ -222,11 +222,11 @@ def testCookieOption(self):
         opt.to_wire(io)
         data = io.getvalue()
         self.assertEqual(data, b"12345678")
-        self.assertEqual(str(opt), "COOKIE 3132333435363738:")
+        self.assertEqual(str(opt), "COOKIE 3132333435363738")
         opt = dns.edns.CookieOption(b"12345678", b"abcdefgh")
         data = opt.to_wire()
         self.assertEqual(data, b"12345678abcdefgh")
-        self.assertEqual(str(opt), "COOKIE 3132333435363738:6162636465666768")
+        self.assertEqual(str(opt), "COOKIE 31323334353637386162636465666768")
         # maximal server
         opt = dns.edns.CookieOption(b"12345678", b"abcdefghabcdefghabcdefghabcdefgh")
         io = BytesIO()