diff --git a/mongoengine/fields.py b/mongoengine/fields.py
index c40491b6..d7c7cf1f 100644
--- a/mongoengine/fields.py
+++ b/mongoengine/fields.py
@@ -213,6 +213,9 @@ class LongField(BaseField):
         if self.max_value is not None and value > self.max_value:
             self.error('Long value is too large')
 
+        if value > 0x7FFFFFFFFFFFFFFF:
+            self.error('Long value is too large')
+
     def prepare_query_value(self, op, value):
         if value is None:
             return value