diff --git a/NEWS b/NEWS
index a9b99e099..3d275ab71 100644
--- a/NEWS
+++ b/NEWS
@@ -32,6 +32,11 @@ New in spot 1.99.7a (not yet released)
     fail to find a deterministic automaton (even if one exists) and
     return a nondeterministic automaton.
 
+  * "autfilt --complement" now also works for non-deterministic
+    automata but will output a deterministic automaton.
+    "autfilt --complement --tgba" will likely output a
+    nondeterministic TGBA.
+
   Library:
 
   * Building products with different dictionaries now raise an
diff --git a/bin/autfilt.cc b/bin/autfilt.cc
index f8c53bb5b..8fde37b84 100644
--- a/bin/autfilt.cc
+++ b/bin/autfilt.cc
@@ -562,17 +562,6 @@ namespace
       if (opt_complement_acc)
 	aut->set_acceptance(aut->acc().num_sets(),
 			    aut->get_acceptance().complement());
-      if (opt_complement)
-	{
-	  if (!spot::is_deterministic(aut))
-	    {
-	      std::cerr << filename << ':'
-			<< haut->loc << (": --complement currently supports "
-					 "only deterministic automata\n");
-	      exit(2);
-	    }
-	  aut = spot::dtwa_complement(aut);
-	}
       if (opt_rem_fin)
 	aut = remove_fin(aut);
       if (opt_dnf_acc)
@@ -658,6 +647,20 @@ namespace
 	    return 0;
 	}
 
+      if (opt_complement)
+	{
+	  if (!spot::is_deterministic(aut))
+	    {
+	      // let's determinize that automaton
+	      spot::postprocessor p;
+	      p.set_type(spot::postprocessor::Generic);
+	      p.set_pref(spot::postprocessor::Deterministic);
+	      p.set_level(level);
+	      aut = p.run(aut);
+	    }
+	  aut = spot::dtwa_complement(aut);
+	}
+
       aut = post.run(aut, nullptr);
 
       if (randomize_st || randomize_tr)
diff --git a/tests/core/complement.test b/tests/core/complement.test
index 92f56e7c1..2c03e0604 100755
--- a/tests/core/complement.test
+++ b/tests/core/complement.test
@@ -1,6 +1,6 @@
 #!/bin/sh
 # -*- coding: utf-8 -*-
-# Copyright (C) 2015 Laboratoire de Recherche et Développement de
+# Copyright (C) 2015, 2016 Laboratoire de Recherche et Développement de
 # l'Epita (LRDE).
 #
 # This file is part of Spot, a model checking library.
@@ -93,6 +93,25 @@ State: 3
 EOF
 diff out expected
 
-
-$ltl2tgba -H 'FGa' | $autfilt --complement 2>out && exit 1
-grep 'deterministic' out
+# The complement of a nondeterministic automaton is currently done via
+# a determinization.
+$ltl2tgba -H 'FGa' | $autfilt --complement >out
+cat >expected <<EOF
+HOA: v1
+States: 2
+Start: 0
+AP: 1 "a"
+acc-name: parity min even 2
+Acceptance: 2 Inf(0) | Fin(1)
+properties: trans-labels explicit-labels trans-acc complete
+properties: deterministic stutter-invariant
+--BODY--
+State: 0
+[0] 1 {1}
+[!0] 0
+State: 1
+[0] 1 {1}
+[!0] 0 {0}
+--END--
+EOF
+diff out expected