diff --git a/src/libraries/Common/src/System/TimeProvider.cs b/src/libraries/Common/src/System/TimeProvider.cs
index e28275393b6ff0..cc7cd3df10a7b3 100644
--- a/src/libraries/Common/src/System/TimeProvider.cs
+++ b/src/libraries/Common/src/System/TimeProvider.cs
@@ -159,11 +159,7 @@ public TimeSpan GetElapsedTime(long startingTimestamp, long endingTimestamp)
         /// </remarks>
         public virtual ITimer CreateTimer(TimerCallback callback, object? state, TimeSpan dueTime, TimeSpan period)
         {
-#if SYSTEM_PRIVATE_CORELIB
-            ArgumentNullException.ThrowIfNull(callback);
-#else
             ArgumentNullException.ThrowIfNull(callback);
-#endif // SYSTEM_PRIVATE_CORELIB
 
             return new SystemTimeProviderTimer(dueTime, period, callback, state);
         }