diff --git a/mocha-dotnet/src/lib/Mocha.Core/OmsImplementations/MemoryOms.cs b/mocha-dotnet/src/lib/Mocha.Core/OmsImplementations/MemoryOms.cs
index 97dfefd..f8fb3ca 100644
--- a/mocha-dotnet/src/lib/Mocha.Core/OmsImplementations/MemoryOms.cs
+++ b/mocha-dotnet/src/lib/Mocha.Core/OmsImplementations/MemoryOms.cs
@@ -165,6 +165,11 @@ public class MemoryOms : Oms
 				if (_Attributes[source].ContainsKey(attribute))
 				{
 					List<AttributeValue> list = _Attributes[source][attribute];
+					list.Sort(delegate (AttributeValue left, AttributeValue right)
+					{
+						return right.EffectiveDate.CompareTo(left.EffectiveDate);
+					});
+
 					foreach (AttributeValue val in list)
 					{
 						if (val.EffectiveDate <= effectiveDate)