diff --git a/gssapi/_win_config.py b/gssapi/_win_config.py
index ccbdb259..c3147fcb 100644
--- a/gssapi/_win_config.py
+++ b/gssapi/_win_config.py
@@ -8,6 +8,7 @@
 
 import os
 import shutil
+import sys
 import ctypes
 
 #: Path to normal KfW installed bin folder
@@ -17,12 +18,16 @@
 )
 #: Download location for KfW
 KFW_DL = "https://web.mit.edu/KERBEROS/dist"
+is64bits = sys.maxsize > 2**32
 
 
 def kfw_available():
     """Return if the main GSSAPI DLL for KfW can be loaded"""
     try:  # to load the main GSSAPI DLL
-        ctypes.WinDLL('gssapi64.dll')
+        if is64bits is True:
+            ctypes.WinDLL('gssapi64.dll')
+        else:
+            ctypes.WinDLL('gssapi32.dll')
     except OSError:  # DLL is not in PATH
         return False
     else:  # DLL is in PATH, everything should work
diff --git a/setup.py b/setup.py
index 37bef146..c4df3364 100755
--- a/setup.py
+++ b/setup.py
@@ -39,6 +39,14 @@ def get_output(*args, **kwargs):
 # get the compile and link args
 kc = "krb5-config"
 posix = os.name != 'nt'
+
+# According to the Python documentation, in order to get the '64-bitness' of
+# the current interpreter, it is more reliable to query the sys.maxsize
+# attribute:
+#
+# Reference:
+# https://docs.python.org/3/library/platform.html#platform.architecture
+is64bits = sys.maxsize > 2**32
 link_args, compile_args = [
     shlex.split(os.environ[e], posix=posix) if e in os.environ else None
     for e in ['GSSAPI_LINKER_ARGS', 'GSSAPI_COMPILER_ARGS']
@@ -114,8 +122,9 @@ def get_output(*args, **kwargs):
     elif winkrb_path:
         compile_args = [
             '-I%s' % os.path.join(winkrb_path, 'include'),
-            '-DMS_WIN64'
         ]
+        if is64bits:
+            compile_args.push('-DMS_WIN64')
     elif os.environ.get('MINGW_PREFIX'):
         compile_args = ['-fPIC']
     else: