diff --git a/181.mcf/BUILD.gn b/181.mcf/BUILD.gn
new file mode 100644
index 0000000..ae421fc
--- /dev/null
+++ b/181.mcf/BUILD.gn
@@ -0,0 +1,23 @@
+# Copyright 2016 The Fuchsia Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+executable("181.mcf") {
+  sources = [
+    "src/implicit.c",
+    "src/mcf.c",
+    "src/mcfutil.c",
+    "src/output.c",
+    "src/pbeampp.c",
+    "src/pbla.c",
+    "src/pflowup.c",
+    "src/psimplex.c",
+    "src/pstart.c",
+    "src/readmin.c",
+    "src/treeup.c",
+  ]
+  defines = [ "WANT_STDC_PROTO" ]
+  data = [
+    "data/ref/input/inp.in",
+  ]
+}
diff --git a/BUILD.gn b/BUILD.gn
index a30b5ae..65bdc04 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -6,6 +6,7 @@
   deps = [
     "176.gcc",
     "177.mesa",
+    "181.mcf",
     "183.equake",
   ]
 }