diff --git a/django/templatetags/admin_modify.py b/django/templatetags/admin_modify.py
index 2938f47a58..fbf9071b01 100644
--- a/django/templatetags/admin_modify.py
+++ b/django/templatetags/admin_modify.py
@@ -180,7 +180,7 @@ def auto_populated_field_script(auto_pop_fields, change = False):
 
         add_values = ' + " " + '.join(['document.getElementById("id_%s").value' % g for g in field.prepopulate_from])
         for f in field.prepopulate_from:
-            t.append('document.getElementById("id_%s").onkeyup = function() { var e = document.getElementById("id_%s"); if(e._changed) { e.value = URLify(%s, %s);} } ' % (f, field.name, add_values, field.maxlength) )
+            t.append('document.getElementById("id_%s").onkeyup = function() { var e = document.getElementById("id_%s"); if(!e._changed) { e.value = URLify(%s, %s);} } ' % (f, field.name, add_values, field.maxlength) )
 
     return ''.join(t)
 auto_populated_field_script = simple_tag(auto_populated_field_script)
diff --git a/django/views/admin/main.py b/django/views/admin/main.py
index 9401254b8e..0c59f78590 100644
--- a/django/views/admin/main.py
+++ b/django/views/admin/main.py
@@ -988,7 +988,7 @@ def _get_template(opts, app_label, add=False, change=False, show_delete=False, f
             else:
                 t.append('document.getElementById("id_%s").onchange = function() { this._changed = true; };' % field.name)
             for f in field.prepopulate_from:
-                t.append('document.getElementById("id_%s").onkeyup = function() { var e = document.getElementById("id_%s"); if (e._changed) { e.value = URLify(%s, %s);}};' % \
+                t.append('document.getElementById("id_%s").onkeyup = function() { var e = document.getElementById("id_%s"); if (!e._changed) { e.value = URLify(%s, %s);}};' % \
                     (f, field.name, ' + " " + '.join(['document.getElementById("id_%s").value' % g for g in field.prepopulate_from]), field.maxlength))
         t.append('</script>\n')
     if change and ordered_objects: