diff --git a/MissionCompletedEntry.cs b/MissionCompletedEntry.cs
index af057ed..8449e75 100644
--- a/MissionCompletedEntry.cs
+++ b/MissionCompletedEntry.cs
@@ -13,7 +13,7 @@ namespace EDJournal {
         public Dictionary<string, Dictionary<ulong, string>> Influences => influences;
 
         protected override void Initialise() {
-            MissionID = JSON.Value<int?>("MissionID") ?? 0;
+            MissionID = JSON.Value<ulong?>("MissionID") ?? 0;
             Name = JSON.Value<string>("Name");
             Faction = JSON.Value<string>("Faction") ?? "";
             TargetFaction = JSON.Value<string>("TargetFaction") ?? "";
@@ -70,7 +70,7 @@ namespace EDJournal {
         public string Commodity { get; set; }
         public int Count { get; set; }
         public int Donated { get; set; }
-        public int MissionID { get; set; }
+        public ulong MissionID { get; set; }
         public string Faction { get; set; }
         public string TargetFaction { get; set; }