diff --git a/src/PyCool/python/PyCool/_internal/definitions.py b/src/PyCool/python/PyCool/_internal/definitions.py
index c51a519357b0d7f6ee33864b93bd7642e1ff7f2a..03b51870ad3135329ef65f242c673c9ca63e560a 100644
--- a/src/PyCool/python/PyCool/_internal/definitions.py
+++ b/src/PyCool/python/PyCool/_internal/definitions.py
@@ -67,15 +67,15 @@ cool_type_aliases = _guess_cool_type_aliases()
 ## Mapping to define typedefs for C++ basic types
 
 basic_types_mapping = {# C++: Python
-                       "unsigned":           "long" ,   # (none)
-                       "unsigned int":       "long" ,   # UInt32, ChannelId
-                       "unsigned long long": "long" ,   # UInt64, UInt63, ValidityKey
+                       "unsigned":           "int" ,   # (none)
+                       "unsigned int":       "int" ,   # UInt32, ChannelId
+                       "unsigned long long": "int" ,   # UInt64, UInt63, ValidityKey
                        "bool":               "bool",   # Bool
                        "unsigned char":      "int",    # UChar
                        "short":              "int",    # Int16
                        "unsigned short":     "int",    # UInt16
                        "int":                "int",    # Int32
-                       "long long":          "long" ,   # Int64
+                       "long long":          "int" ,   # Int64
                        "float":              "float",  # Float
                        "double":             "float",  # Double
                        }