diff --git a/config/passport.js b/config/passport.js
index 0e9524cabe..c08609486c 100755
--- a/config/passport.js
+++ b/config/passport.js
@@ -108,16 +108,23 @@ passport.use(new GitHubStrategy(secrets.github, function(req, accessToken, refre
   } else {
     User.findOne({ github: profile.id }, function(err, existingUser) {
       if (existingUser) return done(null, existingUser);
-      var user = new User();
-      user.email = profile._json.email;
-      user.github = profile.id;
-      user.tokens.push({ kind: 'github', accessToken: accessToken });
-      user.profile.name = profile.displayName;
-      user.profile.picture = profile._json.avatar_url;
-      user.profile.location = profile._json.location;
-      user.profile.website = profile._json.blog;
-      user.save(function(err) {
-        done(err, user);
+      User.findOne({ email: profile._json.email }, function(err, existingEmailUser) {
+        if (existingEmailUser) {
+          req.flash('errors', { msg: 'There is already an account using this email address. Sign in to that account and link it with GitHub manually from Account Settings.' });
+          done(err);
+        } else {
+          var user = new User();
+          user.email = profile._json.email;
+          user.github = profile.id;
+          user.tokens.push({ kind: 'github', accessToken: accessToken });
+          user.profile.name = profile.displayName;
+          user.profile.picture = profile._json.avatar_url;
+          user.profile.location = profile._json.location;
+          user.profile.website = profile._json.blog;
+          user.save(function(err) {
+            done(err, user);
+          });
+        }
       });
     });
   }