diff --git a/changelog/218.bugfix.rst b/changelog/218.bugfix.rst
new file mode 100644
index 000000000..ceb40318e
--- /dev/null
+++ b/changelog/218.bugfix.rst
@@ -0,0 +1 @@
+Fix crashing bug when an NDCube axis after the first is sliced with a numpy.int64.
diff --git a/ndcube/utils/wcs.py b/ndcube/utils/wcs.py
index 981b8ca0c..bcdd60cc9 100644
--- a/ndcube/utils/wcs.py
+++ b/ndcube/utils/wcs.py
@@ -207,7 +207,7 @@ def _wcs_slicer(wcs, missing_axes, item):
             item_ = _slice_list(item_checked)
             new_wcs = wcs.slice(item_)
             for i, it in enumerate(item_checked):
-                if isinstance(it, int):
+                if isinstance(it, (int, np.int64, np.int32)):
                     missing_axes[i] = True
     else:
         raise NotImplementedError("Slicing FITS-WCS by {} not supported.".format(type(item)))