diff --git a/faiss/python/swigfaiss.swig b/faiss/python/swigfaiss.swig
index 0ea93609e3..5c9a7b3fa7 100644
--- a/faiss/python/swigfaiss.swig
+++ b/faiss/python/swigfaiss.swig
@@ -1022,14 +1022,17 @@ PyObject *swig_ptr (PyObject *a)
         return SWIG_NewPointerObj(data, SWIGTYPE_p_bool, 0);
     }
     if(PyArray_TYPE(ao) == NPY_UINT64) {
-#if (__SIZEOF_LONG__ == 8)
+    // Convert npy64 either long or long long  and it depends on how compiler define int64_t.
+    // In the 64bit machine, typically the int64_t should be long but it is not hold for Apple osx.
+    // In this case, we want to convert npy64 to long_Long in osx
+#if __SIZEOF_LONG__ == 8 && !defined(__APPLE__)
         return SWIG_NewPointerObj(data, SWIGTYPE_p_unsigned_long, 0);
 #else
         return SWIG_NewPointerObj(data, SWIGTYPE_p_unsigned_long_long, 0);
 #endif
     }
     if(PyArray_TYPE(ao) == NPY_INT64) {
-#if  (__SIZEOF_LONG__ == 8)
+#if __SIZEOF_LONG__ == 8 && !defined(__APPLE__)
         return SWIG_NewPointerObj(data, SWIGTYPE_p_long, 0);
 #else
         return SWIG_NewPointerObj(data, SWIGTYPE_p_long_long, 0);
@@ -1054,11 +1057,8 @@ struct PythonInterruptCallback: faiss::InterruptCallback {
     }
 
 };
-
-
 %}
 
-
 %init %{
     /* needed, else crash at runtime */
     import_array();
@@ -1121,15 +1121,8 @@ int * cast_integer_to_int_ptr (int64_t x) {
 void * cast_integer_to_void_ptr (int64_t x) {
     return (void*)x;
 }
-
 %}
 
-
-
-
-
-
-
 %inline %{
     void wait() {
         // in gdb, use return to get out of this function