diff --git a/setup.py b/setup.py
--- a/setup.py
+++ b/setup.py
@@ -437,8 +437,10 @@ class PyBuildExt(build_ext):
             # (PYTHONFRAMEWORK is set) to avoid # linking problems when
             # building a framework with different architectures than
             # the one that is currently installed (issue #7473)
-            add_dir_to_list(self.compiler.library_dirs,
-                            sysconfig.get_config_var("LIBDIR"))
+            libdir = sysconfig.get_config_var("LIBDIR")
+            add_dir_to_list(self.compiler.library_dirs, libdir)
+            if sys.maxsize > 2 ** 32 and libdir.endswith('/lib'):
+                add_dir_to_list(self.compiler.library_dirs, libdir + '64')
             add_dir_to_list(self.compiler.include_dirs,
                             sysconfig.get_config_var("INCLUDEDIR"))