diff --git a/scikits/image/filter/ctmf.py b/scikits/image/filter/ctmf.py
index e88cdb54..310534b7 100644
--- a/scikits/image/filter/ctmf.py
+++ b/scikits/image/filter/ctmf.py
@@ -43,6 +43,9 @@ def median_filter(data, mask=None, radius=1, percent=50):
 
     '''
 
+    if data.ndim!=2:
+        raise TypeError("The input 'data' must be a two dimensional array.")
+
     if mask is None:
         mask = np.ones(data.shape, dtype=np.bool)
     mask = np.ascontiguousarray(mask, dtype=np.bool)
diff --git a/scikits/image/filter/tests/test_ctmf.py b/scikits/image/filter/tests/test_ctmf.py
index 02795b3c..1fc26968 100644
--- a/scikits/image/filter/tests/test_ctmf.py
+++ b/scikits/image/filter/tests/test_ctmf.py
@@ -101,5 +101,12 @@ def test_default_values():
     result2 = median_filter(img)
     assert_array_equal(result1, result2)
 
+def test_default_values():
+    img = (np.random.random((20, 20)) * 255).astype(np.uint8)
+    mask = np.ones((20, 20), dtype=np.uint8)
+    result1 = median_filter(img, mask, radius=1, percent=50)
+    result2 = median_filter(img)
+    assert_array_equal(result1, result2)
+
 if __name__ == "__main__":
     run_module_suite()