diff --git a/mcs/class/Mono.Posix/Mono.Unix.Native/Syscall.cs b/mcs/class/Mono.Posix/Mono.Unix.Native/Syscall.cs
index 902ecc2e29fee75341ff1a1454a8c3b1690f5df9..9edf9d3f650f980defb5a5f3734ff4b446e59618 100644
--- a/mcs/class/Mono.Posix/Mono.Unix.Native/Syscall.cs
+++ b/mcs/class/Mono.Posix/Mono.Unix.Native/Syscall.cs
@@ -1165,7 +1165,7 @@ namespace Mono.Unix.Native {
 		EPOLL_CTL_MOD = 3,
 	}
 
-	[StructLayout (LayoutKind.Explicit, Size=12)]
+	[StructLayout (LayoutKind.Explicit, Size=12, Pack=1)]
 	public struct EpollEvent {
 		[FieldOffset (0)]
 		public EpollEvents events;