BUG: pd.crosstab fails when passed multiple columns, margins True and normalize True

doc/source/whatsnew/v1.1.0.rst

@@ -1125,6 +1125,7 @@ Reshaping
 - Bug in :meth:`Series.where` with an empty Series and empty ``cond`` having non-bool dtype (:issue:`34592`)
 - Fixed regression where :meth:`DataFrame.apply` would raise ``ValueError`` for elements whth ``S`` dtype (:issue:`34529`)
 - Bug in :meth:`DataFrame.append` leading to sorting columns even when ``sort=False`` is specified (:issue:`35092`)
+- Bug in func :meth:`crosstab` when using multiple columns with ``margins=True`` and ``normalize=True`` (:issue:`35144`)
 
 Sparse
 ^^^^^^

pandas/core/reshape/pivot.py

@@ -671,9 +671,9 @@ def _normalize(table, normalize, margins: bool, margins_name="All"):
         table_index = table.index
         table_columns = table.columns
 
-        # check if margin name is in (for MI cases) or equal to last
+        # check if margin name is not in (for MI cases) and not equal to last
         # index/column and save the column and index margin
-        if (margins_name not in table.iloc[-1, :].name) | (
+        if (margins_name not in table.iloc[-1, :].name) & (
             margins_name != table.iloc[:, -1].name
         ):
             raise ValueError(f"{margins_name} not in pivoted DataFrame")

pandas/tests/reshape/test_crosstab.py

@@ -698,3 +698,28 @@ def test_margin_normalize(self):
             names=["A", "B"],
         )
         tm.assert_frame_equal(result, expected)
+
+        # GH 35144
+        # use multiple columns with margins and normalization
+        result = crosstab(
+            index=df.C,
+            columns=[df.A, df.B],
+            margins=True,
+            margins_name="margin",
+            normalize=True,
+        )
+        expected = DataFrame(
+            [
+                [0.111111, 0.111111, 0.222222, 0.000000, 0.444444],
+                [0.111111, 0.111111, 0.111111, 0.222222, 0.555556],
+                [0.222222, 0.222222, 0.333333, 0.222222, 1.0],
+            ],
+            index=["large", "small", "margin"],
+        )
+        expected.columns = MultiIndex(
+            levels=[["bar", "foo", "margin"], ["", "one", "two"]],
+            codes=[[0, 0, 1, 1, 2], [1, 2, 1, 2, 0]],
+            names=["A", "B"],
+        )
+        expected.index.name = "C"
+        tm.assert_frame_equal(result, expected)