diff --git a/src/EventSource.js b/src/EventSource.js
index 6a7b146..71b4f93 100644
--- a/src/EventSource.js
+++ b/src/EventSource.js
@@ -108,7 +108,7 @@ class EventSource {
         if (xhr.status >= 200 && xhr.status < 400) {
           if (this.status === this.CONNECTING) {
             this.status = this.OPEN;
-            this.dispatch('open', { type: 'open' });
+            this.dispatch('open', { type: 'open', responseHeaders: xhr.responseHeaders });
             this._logDebug('[EventSource][onreadystatechange][OPEN] Connection opened.');
           }