diff --git a/spectral_cube/spectral_cube.py b/spectral_cube/spectral_cube.py
index a11c0dc6..29ecb856 100644
--- a/spectral_cube/spectral_cube.py
+++ b/spectral_cube/spectral_cube.py
@@ -1060,7 +1060,7 @@ def apply_function(self, function, axis=None, weights=None, unit=None,
         # check dtype first (for argmax/argmin)
         result = function(np.arange(3, dtype=self._data.dtype), **kwargs)
         if 'int' in str(result.dtype):
-            out = np.zeros([nz, nx, ny], dtype=dtype)
+            out = np.zeros([nz, nx, ny], dtype=result.dtype)
         else:
             out = np.empty([nz, nx, ny]) * np.nan