diff --git a/Open.Nat/Discovery/Searcher.cs b/Open.Nat/Discovery/Searcher.cs
index b409fc6..76c7636 100644
--- a/Open.Nat/Discovery/Searcher.cs
+++ b/Open.Nat/Discovery/Searcher.cs
@@ -46,6 +46,8 @@ internal abstract class Searcher
 #if NET35
 		public Task<IEnumerable<NatDevice>> Search(CancellationToken cancelationToken)
 		{
+			cancelationToken.ThrowIfCancellationRequested();
+
 			return Task.Factory.StartNew(_ =>
 			{
 				NatDiscoverer.TraceSource.LogInfo("Searching for: {0}", GetType().Name);
@@ -61,6 +63,8 @@ public Task<IEnumerable<NatDevice>> Search(CancellationToken cancelationToken)
 #else
 		public async Task<IEnumerable<NatDevice>> Search(CancellationToken cancelationToken)
 		{
+			cancelationToken.ThrowIfCancellationRequested();
+
 			await Task.Factory.StartNew(_ =>
 				{
 					NatDiscoverer.TraceSource.LogInfo("Searching for: {0}", GetType().Name);