diff --git a/rest_framework/static/rest_framework/js/ajax-form.js b/rest_framework/static/rest_framework/js/ajax-form.js
index ce17729d1..1483305ff 100644
--- a/rest_framework/static/rest_framework/js/ajax-form.js
+++ b/rest_framework/static/rest_framework/js/ajax-form.js
@@ -37,6 +37,21 @@ function doAjaxSubmit(e) {
 
   if (contentType) {
     data = form.find('[data-override="content"]').val() || ''
+
+    if (contentType === 'multipart/form-data') {
+      // We need to add a boundary parameter to the header
+      // We assume the first valid-looking boundary line in the body is correct
+      // regex is from RFC 2046 appendix A
+      var boundaryCharNoSpace = "0-9A-Z'()+_,-./:=?";
+      var boundaryChar = boundaryCharNoSpace + ' ';
+      var re = new RegExp('^--([' + boundaryChar + ']{0,69}[' + boundaryCharNoSpace + '])[\\s]*?$', 'im');
+      var boundary = data.match(re);
+      if (boundary !== null) {
+        contentType += '; boundary="' + boundary[1] + '"';
+      }
+      // Fix textarea.value EOL normalisation (multipart/form-data should use CR+NL, not NL)
+      data = data.replace(/\n/g, '\r\n');
+    }
   } else {
     contentType = form.attr('enctype') || form.attr('encoding')