diff --git a/changelog/@unreleased/pr-746.v2.yml b/changelog/@unreleased/pr-746.v2.yml
new file mode 100644
index 000000000..0723b5f59
--- /dev/null
+++ b/changelog/@unreleased/pr-746.v2.yml
@@ -0,0 +1,5 @@
+type: fix
+fix:
+  description: union with builtin variant name bug
+  links:
+  - https://github.com/palantir/conjure-python/pull/746
diff --git a/conjure-python-core/src/main/java/com/palantir/conjure/python/processors/PythonIdentifierSanitizer.java b/conjure-python-core/src/main/java/com/palantir/conjure/python/processors/PythonIdentifierSanitizer.java
index 23ec9a510..b4c4d6797 100644
--- a/conjure-python-core/src/main/java/com/palantir/conjure/python/processors/PythonIdentifierSanitizer.java
+++ b/conjure-python-core/src/main/java/com/palantir/conjure/python/processors/PythonIdentifierSanitizer.java
@@ -37,6 +37,7 @@ public final class PythonIdentifierSanitizer {
             "except",
             "exec",
             "finally",
+            "float",
             "for",
             "from",
             "global",
diff --git a/conjure-python-core/src/test/resources/types/example-types.yml b/conjure-python-core/src/test/resources/types/example-types.yml
index aa4814fe4..8c89b4615 100644
--- a/conjure-python-core/src/test/resources/types/example-types.yml
+++ b/conjure-python-core/src/test/resources/types/example-types.yml
@@ -172,3 +172,9 @@ types:
         alias: RecursiveObjectAlias
       CollectionAliasExample:
         alias: map<StringAliasExample, RecursiveObjectAlias>
+      UnionWithBuiltinVariantName:
+        union:
+          # the name of this variant is 'float' which conflicts with the python type 'float'
+          float: double
+          # the python type for this field is 'float' which conflicts with the variant name above
+          double: double
diff --git a/conjure-python-core/src/test/resources/types/expected/package_name/_impl.py b/conjure-python-core/src/test/resources/types/expected/package_name/_impl.py
index 239b3861d..3687260a1 100644
--- a/conjure-python-core/src/test/resources/types/expected/package_name/_impl.py
+++ b/conjure-python-core/src/test/resources/types/expected/package_name/_impl.py
@@ -1594,6 +1594,83 @@ def _property(self, property: int) -> Any:
 product_UnionTypeExampleVisitor.__module__ = "package_name.product"
 
 
+class product_UnionWithBuiltinVariantName(ConjureUnionType):
+    _float_: Optional[float] = None
+    _double: Optional[float] = None
+
+    @builtins.classmethod
+    def _options(cls) -> Dict[str, ConjureFieldDefinition]:
+        return {
+            'float_': ConjureFieldDefinition('float', float),
+            'double': ConjureFieldDefinition('double', float)
+        }
+
+    def __init__(
+            self,
+            float_: Optional[float] = None,
+            double: Optional[float] = None,
+            type_of_union: Optional[str] = None
+            ) -> None:
+        if type_of_union is None:
+            if (float_ is not None) + (double is not None) != 1:
+                raise ValueError('a union must contain a single member')
+
+            if float_ is not None:
+                self._float_ = float_
+                self._type = 'float'
+            if double is not None:
+                self._double = double
+                self._type = 'double'
+
+        elif type_of_union == 'float':
+            if float_ is None:
+                raise ValueError('a union value must not be None')
+            self._float_ = float_
+            self._type = 'float'
+        elif type_of_union == 'double':
+            if double is None:
+                raise ValueError('a union value must not be None')
+            self._double = double
+            self._type = 'double'
+
+    @builtins.property
+    def float_(self) -> Optional[float]:
+        return self._float_
+
+    @builtins.property
+    def double(self) -> Optional[float]:
+        return self._double
+
+    def accept(self, visitor) -> Any:
+        if not isinstance(visitor, product_UnionWithBuiltinVariantNameVisitor):
+            raise ValueError('{} is not an instance of product_UnionWithBuiltinVariantNameVisitor'.format(visitor.__class__.__name__))
+        if self._type == 'float' and self.float_ is not None:
+            return visitor._float(self.float_)
+        if self._type == 'double' and self.double is not None:
+            return visitor._double(self.double)
+
+
+product_UnionWithBuiltinVariantName.__name__ = "UnionWithBuiltinVariantName"
+product_UnionWithBuiltinVariantName.__qualname__ = "UnionWithBuiltinVariantName"
+product_UnionWithBuiltinVariantName.__module__ = "package_name.product"
+
+
+class product_UnionWithBuiltinVariantNameVisitor:
+
+    @abstractmethod
+    def _float(self, float_: float) -> Any:
+        pass
+
+    @abstractmethod
+    def _double(self, double: float) -> Any:
+        pass
+
+
+product_UnionWithBuiltinVariantNameVisitor.__name__ = "UnionWithBuiltinVariantNameVisitor"
+product_UnionWithBuiltinVariantNameVisitor.__qualname__ = "UnionWithBuiltinVariantNameVisitor"
+product_UnionWithBuiltinVariantNameVisitor.__module__ = "package_name.product"
+
+
 class product_UuidExample(ConjureBeanType):
 
     @builtins.classmethod
diff --git a/conjure-python-core/src/test/resources/types/expected/package_name/product/__init__.py b/conjure-python-core/src/test/resources/types/expected/package_name/product/__init__.py
index d92acf564..31cbf3ffd 100644
--- a/conjure-python-core/src/test/resources/types/expected/package_name/product/__init__.py
+++ b/conjure-python-core/src/test/resources/types/expected/package_name/product/__init__.py
@@ -43,6 +43,8 @@
     product_StringExample as StringExample,
     product_UnionTypeExample as UnionTypeExample,
     product_UnionTypeExampleVisitor as UnionTypeExampleVisitor,
+    product_UnionWithBuiltinVariantName as UnionWithBuiltinVariantName,
+    product_UnionWithBuiltinVariantNameVisitor as UnionWithBuiltinVariantNameVisitor,
     product_UuidAliasExample as UuidAliasExample,
     product_UuidExample as UuidExample,
 )