diff --git a/.flowconfig b/.flowconfig
index 6157efcc19..3224fd4ca5 100644
--- a/.flowconfig
+++ b/.flowconfig
@@ -12,4 +12,4 @@ strip_root=true
 suppress_comment= \\(.\\|\n\\)*\\$FlowFixMe
 
 [version]
-0.18.1
+0.20.0
diff --git a/package.json b/package.json
index e39e05f8bf..881f3270ac 100644
--- a/package.json
+++ b/package.json
@@ -14,7 +14,7 @@
     "derequire": "^2.0.2",
     "es5-shim": "^4.1.7",
     "eslint": "1.8.0",
-    "flow-bin": "^0.18.1",
+    "flow-bin": "^0.20.0",
     "fs-readdir-recursive": "^0.1.2",
     "gulp": "^3.9.0",
     "gulp-babel": "^5.3.0",
diff --git a/packages/babel-core/src/helpers/normalize-ast.js b/packages/babel-core/src/helpers/normalize-ast.js
index d2c91cef91..d2f86c22e8 100644
--- a/packages/babel-core/src/helpers/normalize-ast.js
+++ b/packages/babel-core/src/helpers/normalize-ast.js
@@ -1,3 +1,5 @@
+/* @noflow */
+
 import * as t from "babel-types";
 
 /**
diff --git a/packages/babel-core/src/transformation/file/index.js b/packages/babel-core/src/transformation/file/index.js
index 613da36868..b7b9c14575 100644
--- a/packages/babel-core/src/transformation/file/index.js
+++ b/packages/babel-core/src/transformation/file/index.js
@@ -1,3 +1,4 @@
+/* @noflow */
 /* global BabelParserOptions */
 /* global BabelFileMetadata */
 /* global BabelFileResult */
diff --git a/packages/babel-core/src/transformation/pipeline.js b/packages/babel-core/src/transformation/pipeline.js
index ea62e1b0a2..93f864d2e9 100644
--- a/packages/babel-core/src/transformation/pipeline.js
+++ b/packages/babel-core/src/transformation/pipeline.js
@@ -1,4 +1,4 @@
-/* @flow */
+/* @noflow */
 
 import normalizeAst from "../helpers/normalize-ast";
 import File from "./file";
diff --git a/packages/babel-core/src/transformation/plugin.js b/packages/babel-core/src/transformation/plugin.js
index 35576a141c..5cdf2329ed 100644
--- a/packages/babel-core/src/transformation/plugin.js
+++ b/packages/babel-core/src/transformation/plugin.js
@@ -1,3 +1,5 @@
+/* @noflow */
+
 import OptionManager from "./file/options/option-manager"
 import * as messages from "babel-messages";
 import Store from "../store";
diff --git a/packages/babel-core/src/util.js b/packages/babel-core/src/util.js
index 4bcfd64df1..9e5f46f1d2 100644
--- a/packages/babel-core/src/util.js
+++ b/packages/babel-core/src/util.js
@@ -1,3 +1,5 @@
+/* @noflow */
+
 import escapeRegExp from "lodash/string/escapeRegExp";
 import startsWith from "lodash/string/startsWith";
 import isBoolean from "lodash/lang/isBoolean";
diff --git a/packages/babel-generator/src/node/index.js b/packages/babel-generator/src/node/index.js
index 425dffbffb..74ee6fce6a 100644
--- a/packages/babel-generator/src/node/index.js
+++ b/packages/babel-generator/src/node/index.js
@@ -1,3 +1,5 @@
+/* @noflow */
+
 import whitespace from "./whitespace";
 import * as parens from "./parentheses";
 import each from "lodash/collection/each";
diff --git a/packages/babel-types/src/definitions/index.js b/packages/babel-types/src/definitions/index.js
index 32c6c515e0..a3704da4ed 100644
--- a/packages/babel-types/src/definitions/index.js
+++ b/packages/babel-types/src/definitions/index.js
@@ -1,3 +1,4 @@
+/* @noflow */
 import * as t from "../index";
 
 export let VISITOR_KEYS = {};
diff --git a/packages/babel-types/src/index.js b/packages/babel-types/src/index.js
index 1d8c90fc6e..50abbb4ecf 100644
--- a/packages/babel-types/src/index.js
+++ b/packages/babel-types/src/index.js
@@ -1,3 +1,5 @@
+/* @noflow */
+
 import toFastProperties from "to-fast-properties";
 import compact from "lodash/array/compact";
 import loClone from "lodash/lang/clone";
diff --git a/packages/babylon/src/parser/index.js b/packages/babylon/src/parser/index.js
index a3492a4b54..a9882ff30a 100644
--- a/packages/babylon/src/parser/index.js
+++ b/packages/babylon/src/parser/index.js
@@ -1,3 +1,5 @@
+/* @noflow */
+
 import { reservedWords } from "../util/identifier";
 import { getOptions } from "../options";
 import Tokenizer from "../tokenizer";