diff --git a/DFA.fs b/DFA.fs
index 3f662dd..1717209 100644
--- a/DFA.fs
+++ b/DFA.fs
@@ -69,4 +69,14 @@ let rec processCharArray (dfa: DFA) (state: String) (charArr: Char list) =
 /// Returns whether the DFA accepts this word
 let acceptsWord (dfa: DFA) (word: String) =
     dfa.acceptingStates
-    |> List.contains (processCharArray dfa dfa.beginState (Seq.toList word))
\ No newline at end of file
+    |> List.contains (processCharArray dfa dfa.beginState (Seq.toList word))
+
+let complement (dfa: DFA) : DFA =
+    {
+        sigma = dfa.sigma;
+        states = dfa.states;
+        delta = dfa.delta;
+        beginState = dfa.beginState;
+        acceptingStates = dfa.states
+            |> List.filter (fun x -> not (List.contains x dfa.acceptingStates))
+    }