diff --git a/lib/icingadb/icingadb-objects.cpp b/lib/icingadb/icingadb-objects.cpp
index 101c31bad88..2061ad6bca7 100644
--- a/lib/icingadb/icingadb-objects.cpp
+++ b/lib/icingadb/icingadb-objects.cpp
@@ -1386,8 +1386,8 @@ bool IcingaDB::PrepareObject(const ConfigObject::Ptr& object, Dictionary::Ptr& a
 			auto begin (notification->GetTimes()->Get("begin"));
 			auto end (notification->GetTimes()->Get("end"));
 
-			attributes->Set("times_begin", begin == Empty ? Empty : Value(std::round((double)begin)));
-			attributes->Set("times_end", end == Empty ? Empty : Value(std::round((double)end)));
+			attributes->Set("times_begin", begin == Empty || (double)begin < 0 ? Empty : Value(std::round((double)begin)));
+			attributes->Set("times_end", end == Empty || (double)end < 0 ? Empty : Value(std::round((double)end)));
 		}
 
 		attributes->Set("notification_interval", notification->GetInterval());