diff --git a/lib/collection/proxy-config.js b/lib/collection/proxy-config.js
index <HASH>..<HASH> 100644
--- a/lib/collection/proxy-config.js
+++ b/lib/collection/proxy-config.js
@@ -1,4 +1,5 @@
 var _ = require('../util').lodash,
+    querystring = require('querystring'),
     Property = require('./property').Property,
     PropertyList = require('./property-list').PropertyList,
     Url = require('./url').Url,
@@ -232,10 +233,10 @@ _.assign(ProxyConfig.prototype, /** @lends ProxyConfig.prototype */ {
         // Add authentication method to URL if the same is requested. We do it this way because
         // this is how `postman-request` library accepts auth credentials in its proxy configuration.
         if (this.authenticate) {
-            auth = (this.username || E);
+            auth = querystring.escape(this.username || E);
 
             if (this.password) {
-                auth += (COLON + (this.password || E));
+                auth += COLON + querystring.escape(this.password);
             }
 
             if (auth) {
Escape username and password in proxy auth