diff --git a/lib/browser/guest-window-manager.js b/lib/browser/guest-window-manager.js
index 0bb7970f82e9..3240161b2de6 100644
--- a/lib/browser/guest-window-manager.js
+++ b/lib/browser/guest-window-manager.js
@@ -122,6 +122,15 @@ const createGuest = function (embedder, url, frameName, options, postData) {
     const loadOptions = {}
     if (postData) {
       loadOptions.postData = postData
+      loadOptions.extraHeaders = 'content-type: application/x-www-form-urlencoded'
+      if (postData.length) {
+        const postDataFront = postData[0].bytes.toString()
+        const regex = new RegExp(/^--.*[^-\r\n]/)
+        const boundary = regex.exec(postDataFront)
+        if (boundary) {
+          loadOptions.extraHeaders = `content-type: multipart/form-data; boundary=${boundary[0].substr(2)}`
+        }
+      }
     }
     guest.loadURL(url, loadOptions)
   }