diff --git a/chanfig/flat_dict.py b/chanfig/flat_dict.py
index 1608e952..b527e412 100644
--- a/chanfig/flat_dict.py
+++ b/chanfig/flat_dict.py
@@ -302,6 +302,10 @@ def set(self, name: Any, value: Any) -> None:
         if name in self and isinstance(self.get(name), Variable):
             self.get(name).set(value)
         else:
+            if name in get_annotations(self):
+                anno = get_annotations(self)[name]
+                if isinstance(anno, type) and not isinstance(value, anno):
+                    value = anno(value)
             dict.__setitem__(self, name, value)
 
     def __setitem__(self, name: Any, value: Any) -> None:
diff --git a/tests/test_flat_dict.py b/tests/test_flat_dict.py
index 474f4235..4576ed65 100644
--- a/tests/test_flat_dict.py
+++ b/tests/test_flat_dict.py
@@ -78,9 +78,8 @@ def test_validate(self):
         ConfigDict(int_value=1, str_value="1", float_value=1.0)
         with raises(TypeError):
             ConfigDict(int_value="1", str_value="1", float_value=1.0)
-        with raises(TypeError):
-            self.dict.int_value = "1"
-            self.dict.validate()
+        self.dict.int_value = "1"
+        assert isinstance(self.dict.int_value, int)
         ConfigDict(list_int=[1, 2, 3])
         with raises(TypeError):
             ConfigDict(list_int=[1, "2", 3])