diff --git a/skimage/measure/_regionprops.py b/skimage/measure/_regionprops.py
index 5f91de3e..1655ec61 100644
--- a/skimage/measure/_regionprops.py
+++ b/skimage/measure/_regionprops.py
@@ -491,6 +491,9 @@ def regionprops(label_image, intensity_image=None, cache=True):
     if label_image.ndim != 2:
         raise TypeError('Only 2-D images supported.')
 
+    if not np.issubdtype(label_image.dtype, np.integer):
+        raise TypeError('Label image must be of integral type.')
+
     regions = []
 
     objects = ndi.find_objects(label_image)
diff --git a/skimage/measure/tests/test_regionprops.py b/skimage/measure/tests/test_regionprops.py
index 487d782e..514b84d3 100644
--- a/skimage/measure/tests/test_regionprops.py
+++ b/skimage/measure/tests/test_regionprops.py
@@ -32,7 +32,9 @@ def test_all_props():
 def test_dtype():
     regionprops(np.zeros((10, 10), dtype=np.int))
     regionprops(np.zeros((10, 10), dtype=np.uint))
-    assert_raises((TypeError, RuntimeError), regionprops,
+    assert_raises((TypeError), regionprops,
+                  np.zeros((10, 10), dtype=np.float))
+    assert_raises((TypeError), regionprops,
                   np.zeros((10, 10), dtype=np.double))