diff --git a/src/NHibernate/Criterion/PropertyExpression.cs b/src/NHibernate/Criterion/PropertyExpression.cs
index cb5c7c9512f..84ec0d96faa 100644
--- a/src/NHibernate/Criterion/PropertyExpression.cs
+++ b/src/NHibernate/Criterion/PropertyExpression.cs
@@ -124,7 +124,7 @@ public override TypedValue[] GetTypedValues(ICriteria criteria, ICriteriaQuery c
 		/// <summary></summary>
 		public override string ToString()
 		{
-			return (_lhsProjection ?? (object)_lhsPropertyName) + Op + _rhsPropertyName;
+			return (_lhsProjection ?? (object)_lhsPropertyName) + Op + (_rhsProjection ?? (object)_rhsPropertyName);
 		}
 
 		public override IProjection[] GetProjections()