diff --git a/packages/babel-helper-define-map/src/index.js b/packages/babel-helper-define-map/src/index.js
index 131b02a8c755..653674755507 100644
--- a/packages/babel-helper-define-map/src/index.js
+++ b/packages/babel-helper-define-map/src/index.js
@@ -55,6 +55,7 @@ export function push(mutatorMap: Object, node: Object, kind: string, file, scope
     value = node.value;
   } else if (t.isObjectMethod(node) || t.isClassMethod(node)) {
     value = t.functionExpression(null, node.params, node.body, node.generator, node.async);
+    value.returnType = node.returnType;
   }
 
   let inheritedKind = toKind(node);
diff --git a/packages/babel-plugin-transform-es2015-classes/src/loose.js b/packages/babel-plugin-transform-es2015-classes/src/loose.js
index e44ebe7089c7..5c9122bacc0c 100644
--- a/packages/babel-plugin-transform-es2015-classes/src/loose.js
+++ b/packages/babel-plugin-transform-es2015-classes/src/loose.js
@@ -17,6 +17,7 @@ export default class LooseClassTransformer extends VanillaTransformer {
       let methodName = t.memberExpression(classRef, node.key, node.computed || t.isLiteral(node.key));
 
       let func = t.functionExpression(null, node.params, node.body, node.generator, node.async);
+      func.returnType = node.returnType;
       let key = t.toComputedKey(node, node.key);
       if (t.isStringLiteral(key)) {
         func = nameFunction({
diff --git a/packages/babel-plugin-transform-es2015-classes/test/fixtures/loose/method-return-type-annotation/actual.js b/packages/babel-plugin-transform-es2015-classes/test/fixtures/loose/method-return-type-annotation/actual.js
new file mode 100644
index 000000000000..918e7469b6c7
--- /dev/null
+++ b/packages/babel-plugin-transform-es2015-classes/test/fixtures/loose/method-return-type-annotation/actual.js
@@ -0,0 +1,6 @@
+// @flow
+class C {
+  m(x: number): string {
+    return 'a';
+  }
+}
diff --git a/packages/babel-plugin-transform-es2015-classes/test/fixtures/loose/method-return-type-annotation/expected.js b/packages/babel-plugin-transform-es2015-classes/test/fixtures/loose/method-return-type-annotation/expected.js
new file mode 100644
index 000000000000..c426f3b6ac27
--- /dev/null
+++ b/packages/babel-plugin-transform-es2015-classes/test/fixtures/loose/method-return-type-annotation/expected.js
@@ -0,0 +1,12 @@
+// @flow
+var C = function () {
+  function C() {
+    babelHelpers.classCallCheck(this, C);
+  }
+
+  C.prototype.m = function m(x: number): string {
+    return 'a';
+  };
+
+  return C;
+}();
diff --git a/packages/babel-plugin-transform-es2015-classes/test/fixtures/loose/method-return-type-annotation/options.json b/packages/babel-plugin-transform-es2015-classes/test/fixtures/loose/method-return-type-annotation/options.json
new file mode 100644
index 000000000000..8c5be0363c3a
--- /dev/null
+++ b/packages/babel-plugin-transform-es2015-classes/test/fixtures/loose/method-return-type-annotation/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": ["external-helpers", "transform-es2015-function-name", ["transform-es2015-classes", { "loose": true }], "transform-es2015-spread", "transform-es2015-block-scoping", "syntax-flow"]
+}
diff --git a/packages/babel-plugin-transform-es2015-classes/test/fixtures/spec/method-return-type-annotation/actual.js b/packages/babel-plugin-transform-es2015-classes/test/fixtures/spec/method-return-type-annotation/actual.js
new file mode 100644
index 000000000000..918e7469b6c7
--- /dev/null
+++ b/packages/babel-plugin-transform-es2015-classes/test/fixtures/spec/method-return-type-annotation/actual.js
@@ -0,0 +1,6 @@
+// @flow
+class C {
+  m(x: number): string {
+    return 'a';
+  }
+}
diff --git a/packages/babel-plugin-transform-es2015-classes/test/fixtures/spec/method-return-type-annotation/expected.js b/packages/babel-plugin-transform-es2015-classes/test/fixtures/spec/method-return-type-annotation/expected.js
new file mode 100644
index 000000000000..97a5968f04da
--- /dev/null
+++ b/packages/babel-plugin-transform-es2015-classes/test/fixtures/spec/method-return-type-annotation/expected.js
@@ -0,0 +1,14 @@
+// @flow
+var C = function () {
+  function C() {
+    babelHelpers.classCallCheck(this, C);
+  }
+
+  babelHelpers.createClass(C, [{
+    key: 'm',
+    value: function m(x: number): string {
+      return 'a';
+    }
+  }]);
+  return C;
+}();
diff --git a/packages/babel-plugin-transform-es2015-classes/test/fixtures/spec/method-return-type-annotation/options.json b/packages/babel-plugin-transform-es2015-classes/test/fixtures/spec/method-return-type-annotation/options.json
new file mode 100644
index 000000000000..f5d949b7eab3
--- /dev/null
+++ b/packages/babel-plugin-transform-es2015-classes/test/fixtures/spec/method-return-type-annotation/options.json
@@ -0,0 +1,3 @@
+{
+  "plugins": ["external-helpers", "transform-es2015-function-name", "transform-es2015-classes", "transform-es2015-spread", "transform-es2015-block-scoping", "syntax-flow"]
+}
diff --git a/packages/babel-plugin-transform-flow-comments/test/fixtures/flow-comments/transformed-class-method-loose-return-type-annotation/actual.js b/packages/babel-plugin-transform-flow-comments/test/fixtures/flow-comments/transformed-class-method-loose-return-type-annotation/actual.js
new file mode 100644
index 000000000000..918e7469b6c7
--- /dev/null
+++ b/packages/babel-plugin-transform-flow-comments/test/fixtures/flow-comments/transformed-class-method-loose-return-type-annotation/actual.js
@@ -0,0 +1,6 @@
+// @flow
+class C {
+  m(x: number): string {
+    return 'a';
+  }
+}
diff --git a/packages/babel-plugin-transform-flow-comments/test/fixtures/flow-comments/transformed-class-method-loose-return-type-annotation/expected.js b/packages/babel-plugin-transform-flow-comments/test/fixtures/flow-comments/transformed-class-method-loose-return-type-annotation/expected.js
new file mode 100644
index 000000000000..82c2e802ada8
--- /dev/null
+++ b/packages/babel-plugin-transform-flow-comments/test/fixtures/flow-comments/transformed-class-method-loose-return-type-annotation/expected.js
@@ -0,0 +1,14 @@
+'use strict';
+
+// @flow
+var C = function () {
+  function C() {
+    babelHelpers.classCallCheck(this, C);
+  }
+
+  C.prototype.m = function m(x /*: number*/) /*: string*/ {
+    return 'a';
+  };
+
+  return C;
+}();
diff --git a/packages/babel-plugin-transform-flow-comments/test/fixtures/flow-comments/transformed-class-method-loose-return-type-annotation/options.json b/packages/babel-plugin-transform-flow-comments/test/fixtures/flow-comments/transformed-class-method-loose-return-type-annotation/options.json
new file mode 100644
index 000000000000..5c34f0f1ea77
--- /dev/null
+++ b/packages/babel-plugin-transform-flow-comments/test/fixtures/flow-comments/transformed-class-method-loose-return-type-annotation/options.json
@@ -0,0 +1,4 @@
+{
+  "presets": [["es2015", { "loose": true }]],
+  "plugins": ["transform-flow-comments", "external-helpers"]
+}
diff --git a/packages/babel-plugin-transform-flow-comments/test/fixtures/flow-comments/transformed-class-method-return-type-annotation/actual.js b/packages/babel-plugin-transform-flow-comments/test/fixtures/flow-comments/transformed-class-method-return-type-annotation/actual.js
new file mode 100644
index 000000000000..918e7469b6c7
--- /dev/null
+++ b/packages/babel-plugin-transform-flow-comments/test/fixtures/flow-comments/transformed-class-method-return-type-annotation/actual.js
@@ -0,0 +1,6 @@
+// @flow
+class C {
+  m(x: number): string {
+    return 'a';
+  }
+}
diff --git a/packages/babel-plugin-transform-flow-comments/test/fixtures/flow-comments/transformed-class-method-return-type-annotation/expected.js b/packages/babel-plugin-transform-flow-comments/test/fixtures/flow-comments/transformed-class-method-return-type-annotation/expected.js
new file mode 100644
index 000000000000..355d1ce274f4
--- /dev/null
+++ b/packages/babel-plugin-transform-flow-comments/test/fixtures/flow-comments/transformed-class-method-return-type-annotation/expected.js
@@ -0,0 +1,16 @@
+'use strict';
+
+// @flow
+var C = function () {
+  function C() {
+    babelHelpers.classCallCheck(this, C);
+  }
+
+  babelHelpers.createClass(C, [{
+    key: 'm',
+    value: function m(x /*: number*/) /*: string*/ {
+      return 'a';
+    }
+  }]);
+  return C;
+}();
diff --git a/packages/babel-plugin-transform-flow-comments/test/fixtures/flow-comments/transformed-class-method-return-type-annotation/options.json b/packages/babel-plugin-transform-flow-comments/test/fixtures/flow-comments/transformed-class-method-return-type-annotation/options.json
new file mode 100644
index 000000000000..8116b856f31a
--- /dev/null
+++ b/packages/babel-plugin-transform-flow-comments/test/fixtures/flow-comments/transformed-class-method-return-type-annotation/options.json
@@ -0,0 +1,4 @@
+{
+  "presets": ["es2015"],
+  "plugins": ["transform-flow-comments", "external-helpers"]
+}
diff --git a/packages/babel-plugin-transform-flow-strip-types/test/fixtures/regression/transformed-class-method-loose-return-type-annotation/actual.js b/packages/babel-plugin-transform-flow-strip-types/test/fixtures/regression/transformed-class-method-loose-return-type-annotation/actual.js
new file mode 100644
index 000000000000..918e7469b6c7
--- /dev/null
+++ b/packages/babel-plugin-transform-flow-strip-types/test/fixtures/regression/transformed-class-method-loose-return-type-annotation/actual.js
@@ -0,0 +1,6 @@
+// @flow
+class C {
+  m(x: number): string {
+    return 'a';
+  }
+}
diff --git a/packages/babel-plugin-transform-flow-strip-types/test/fixtures/regression/transformed-class-method-loose-return-type-annotation/expected.js b/packages/babel-plugin-transform-flow-strip-types/test/fixtures/regression/transformed-class-method-loose-return-type-annotation/expected.js
new file mode 100644
index 000000000000..8892b9861a2c
--- /dev/null
+++ b/packages/babel-plugin-transform-flow-strip-types/test/fixtures/regression/transformed-class-method-loose-return-type-annotation/expected.js
@@ -0,0 +1,13 @@
+'use strict';
+
+var C = function () {
+  function C() {
+    babelHelpers.classCallCheck(this, C);
+  }
+
+  C.prototype.m = function m(x) {
+    return 'a';
+  };
+
+  return C;
+}();
diff --git a/packages/babel-plugin-transform-flow-strip-types/test/fixtures/regression/transformed-class-method-loose-return-type-annotation/options.json b/packages/babel-plugin-transform-flow-strip-types/test/fixtures/regression/transformed-class-method-loose-return-type-annotation/options.json
new file mode 100644
index 000000000000..85b91fb83fbe
--- /dev/null
+++ b/packages/babel-plugin-transform-flow-strip-types/test/fixtures/regression/transformed-class-method-loose-return-type-annotation/options.json
@@ -0,0 +1,4 @@
+{
+  "presets": [["es2015", { "loose": true }]],
+  "plugins": ["transform-flow-strip-types", "external-helpers"]
+}
diff --git a/packages/babel-plugin-transform-flow-strip-types/test/fixtures/regression/transformed-class-method-return-type-annotation/actual.js b/packages/babel-plugin-transform-flow-strip-types/test/fixtures/regression/transformed-class-method-return-type-annotation/actual.js
new file mode 100644
index 000000000000..918e7469b6c7
--- /dev/null
+++ b/packages/babel-plugin-transform-flow-strip-types/test/fixtures/regression/transformed-class-method-return-type-annotation/actual.js
@@ -0,0 +1,6 @@
+// @flow
+class C {
+  m(x: number): string {
+    return 'a';
+  }
+}
diff --git a/packages/babel-plugin-transform-flow-strip-types/test/fixtures/regression/transformed-class-method-return-type-annotation/expected.js b/packages/babel-plugin-transform-flow-strip-types/test/fixtures/regression/transformed-class-method-return-type-annotation/expected.js
new file mode 100644
index 000000000000..fd8f42aacd69
--- /dev/null
+++ b/packages/babel-plugin-transform-flow-strip-types/test/fixtures/regression/transformed-class-method-return-type-annotation/expected.js
@@ -0,0 +1,15 @@
+'use strict';
+
+var C = function () {
+  function C() {
+    babelHelpers.classCallCheck(this, C);
+  }
+
+  babelHelpers.createClass(C, [{
+    key: 'm',
+    value: function m(x) {
+      return 'a';
+    }
+  }]);
+  return C;
+}();
diff --git a/packages/babel-plugin-transform-flow-strip-types/test/fixtures/regression/transformed-class-method-return-type-annotation/options.json b/packages/babel-plugin-transform-flow-strip-types/test/fixtures/regression/transformed-class-method-return-type-annotation/options.json
new file mode 100644
index 000000000000..9d96c07c6bf8
--- /dev/null
+++ b/packages/babel-plugin-transform-flow-strip-types/test/fixtures/regression/transformed-class-method-return-type-annotation/options.json
@@ -0,0 +1,4 @@
+{
+  "presets": ["es2015"],
+  "plugins": ["transform-flow-strip-types", "external-helpers"]
+}