diff --git a/BizHawk.Common/UndoHistory.cs b/BizHawk.Common/UndoHistory.cs
index 05be8e689b..eef6b72104 100644
--- a/BizHawk.Common/UndoHistory.cs
+++ b/BizHawk.Common/UndoHistory.cs
@@ -8,8 +8,11 @@ namespace BizHawk.Common
 		private List<List<T>> _history = new List<List<T>>();
 		private int _curPos; // 1-based
 
+		public int MaxUndoLevels { get; set; }
+
 		public UndoHistory(bool enabled)
 		{
+			MaxUndoLevels = 5;
 			Enabled = enabled;
 		}
 
@@ -54,6 +57,15 @@ namespace BizHawk.Common
 					}
 				}
 
+				// TODO: don't assume we are one over, since MaxUndoLevels is public, it could be set to a small number after a large list has occured
+				if (_history.Count > MaxUndoLevels)
+				{
+					foreach (var item in _history.Take(_history.Count - MaxUndoLevels))
+					{
+						_history.Remove(item);
+					}
+				}
+
 				_history.Add(newState.ToList());
 				_curPos = _history.Count;
 			}