diff --git a/src/rasterstats/io.py b/src/rasterstats/io.py
index 04e2687..a54eecc 100644
--- a/src/rasterstats/io.py
+++ b/src/rasterstats/io.py
@@ -9,6 +9,7 @@
 import rasterio
 import warnings
 from rasterio.transform import guard_transform
+from rasterio.enums import MaskFlags
 from affine import Affine
 import numpy as np
 try:
@@ -305,6 +306,11 @@ def read(self, bounds=None, window=None, masked=False):
                 self.array, window=win, nodata=nodata, masked=masked)
         elif self.src:
             # It's an open rasterio dataset
+            if all(MaskFlags.per_dataset in flags for flags in self.src.mask_flag_enums):
+                if not masked:
+                    masked = True
+                    warnings.warn("Setting masked to True because dataset mask has been detected")
+
             new_array = self.src.read(
                 self.band, window=win, boundless=True, masked=masked)
 
diff --git a/tests/data/dataset_mask.tif b/tests/data/dataset_mask.tif
new file mode 100644
index 0000000..0207d12
Binary files /dev/null and b/tests/data/dataset_mask.tif differ
diff --git a/tests/test_zonal.py b/tests/test_zonal.py
index 898b8eb..ecd5138 100644
--- a/tests/test_zonal.py
+++ b/tests/test_zonal.py
@@ -204,6 +204,14 @@ def test_nodata():
     assert '1.0' not in stats[0]
 
 
+def test_dataset_mask():
+    polygons = os.path.join(DATA, 'polygons.shp')
+    raster = os.path.join(DATA, 'dataset_mask.tif')
+    stats = zonal_stats(polygons, raster, stats="*")
+    assert stats[0]['count'] == 75
+    assert stats[1]['count'] == 0
+
+
 def test_partial_overlap():
     polygons = os.path.join(DATA, 'polygons_partial_overlap.shp')
     stats = zonal_stats(polygons, raster, stats="count")