diff --git a/setup.py b/setup.py
index 591e50bbc..2ceb9bfbb 100644
--- a/setup.py
+++ b/setup.py
@@ -72,7 +72,7 @@ MOD_NAMES = [
 # which is really known only after finalize_options
 # http://stackoverflow.com/questions/724664/python-distutils-how-to-get-a-compiler-that-is-going-to-be-used
 compile_options =  {
-    'msvc': ['/Ox', '/EHsc', '/openmp'],
+    'msvc': ['/Ox', '/EHsc'],
     'mingw32' : ['-O3', '-Wno-strict-prototypes', '-Wno-unused-function'],
     'other' : ['-O3', '-Wno-strict-prototypes', '-Wno-unused-function']
 }
@@ -85,6 +85,10 @@ link_options = {
 }
 
 
+if os.environ.get('USE_OPENMP') == '1':
+    compile_options['msvc'].append('/openmp')
+
+
 if not sys.platform.startswith('darwin'):
     compile_options['other'].append('-fopenmp')
     link_options['other'].append('-fopenmp')