diff --git a/altair/vegalite/v3/api.py b/altair/vegalite/v3/api.py
index f8ec4a191..84cd23b76 100644
--- a/altair/vegalite/v3/api.py
+++ b/altair/vegalite/v3/api.py
@@ -537,7 +537,9 @@ def properties(self, **kwargs):
                 # For backward compatibility with old selection interface.
                 setattr(copy, key, {val.name: val.selection})
             else:
-                self.validate_property(key, val)
+                # Don't validate data, because it hasn't been processed.
+                if key != 'data':
+                    self.validate_property(key, val)
                 setattr(copy, key, val)
         return copy
 
diff --git a/altair/vegalite/v3/tests/test_api.py b/altair/vegalite/v3/tests/test_api.py
index 296fe437f..426a85559 100644
--- a/altair/vegalite/v3/tests/test_api.py
+++ b/altair/vegalite/v3/tests/test_api.py
@@ -640,3 +640,11 @@ def test_repeat():
     assert 'columns' not in dct2
     assert dct2['spec']['encoding']['x']['field'] == {'repeat': 'row'}
     assert dct2['spec']['encoding']['y']['field'] == {'repeat': 'column'}
+
+
+def test_data_property():
+    data = pd.DataFrame({'x': [1, 2, 3], 'y': list('ABC')})
+    chart1 = alt.Chart(data).mark_point()
+    chart2 = alt.Chart().mark_point().properties(data=data)
+
+    assert chart1.to_dict() == chart2.to_dict()
\ No newline at end of file