diff --git a/packages/rollup-plugin-babel/src/index.js b/packages/rollup-plugin-babel/src/index.js
index f93572f09..315e69b6f 100644
--- a/packages/rollup-plugin-babel/src/index.js
+++ b/packages/rollup-plugin-babel/src/index.js
@@ -29,9 +29,9 @@ export default function babel ( options ) {
 	let externalHelpersWhitelist = null;
 	if ( options.externalHelpersWhitelist ) externalHelpersWhitelist = options.externalHelpersWhitelist;
 	delete options.externalHelpersWhitelist;
-  
+
 	let warn = msg => console.warn(msg); // eslint-disable-line no-console
-  
+
 	return {
 		name: 'babel',
 
@@ -68,9 +68,13 @@ export default function babel ( options ) {
 
 			if ( usedHelpers.length ) {
 				if ( helpers === BUNDLED ) {
-					if ( !externalHelpers ) transformed.code += `\n\nimport * as babelHelpers from '${HELPERS}';`;
-				} else if ( helpers === RUNTIME && !runtimeHelpers ) {
-					throw new Error( 'Runtime helpers are not enabled. Either exclude the transform-runtime Babel plugin or pass the `runtimeHelpers: true` option. See https://github.com/rollup/rollup-plugin-babel#configuring-babel for more information' );
+					if ( !externalHelpers ) {
+						transformed.code += `\n\nimport * as babelHelpers from '${HELPERS}';`;
+					}
+				} else if ( helpers === RUNTIME ) {
+					if ( !runtimeHelpers ) {
+						throw new Error( 'Runtime helpers are not enabled. Either exclude the transform-runtime Babel plugin or pass the `runtimeHelpers: true` option. See https://github.com/rollup/rollup-plugin-babel#configuring-babel for more information' );
+					}
 				} else {
 					usedHelpers.forEach( helper => {
 						if ( inlineHelpers[ helper ] ) {
diff --git a/packages/rollup-plugin-babel/src/preflightCheck.js b/packages/rollup-plugin-babel/src/preflightCheck.js
index 3abfeed0f..e0f90b869 100644
--- a/packages/rollup-plugin-babel/src/preflightCheck.js
+++ b/packages/rollup-plugin-babel/src/preflightCheck.js
@@ -22,7 +22,7 @@ export default function preflightCheck ( options, dir ) {
 
 		if ( !~check.indexOf( 'export default' ) && !~check.indexOf( 'export { Foo as default }' ) ) throw new Error( 'It looks like your Babel configuration specifies a module transformer. Please disable it. See https://github.com/rollup/rollup-plugin-babel#configuring-babel for more information' );
 
-		if ( ~check.indexOf( 'import _classCallCheck from "babel-runtime' ) ) helpers = RUNTIME;
+		if ( /import _classCallCheck from ["']babel-runtime/.test( check ) ) helpers = RUNTIME;
 		else if ( ~check.indexOf( 'function _classCallCheck' ) ) helpers = INLINE;
 		else if ( ~check.indexOf( 'babelHelpers' ) ) helpers = BUNDLED;
 
diff --git a/packages/rollup-plugin-babel/test/samples/runtime-helpers-duplicated/.babelrc b/packages/rollup-plugin-babel/test/samples/runtime-helpers-duplicated/.babelrc
new file mode 100644
index 000000000..30d8df05e
--- /dev/null
+++ b/packages/rollup-plugin-babel/test/samples/runtime-helpers-duplicated/.babelrc
@@ -0,0 +1,4 @@
+{
+	"presets": [ "es2015-rollup" ],
+	"plugins": "transform-runtime"
+}
diff --git a/packages/rollup-plugin-babel/test/samples/runtime-helpers-duplicated/Bar.js b/packages/rollup-plugin-babel/test/samples/runtime-helpers-duplicated/Bar.js
new file mode 100644
index 000000000..87c1ff593
--- /dev/null
+++ b/packages/rollup-plugin-babel/test/samples/runtime-helpers-duplicated/Bar.js
@@ -0,0 +1 @@
+export default class Bar {}
diff --git a/packages/rollup-plugin-babel/test/samples/runtime-helpers-duplicated/main.js b/packages/rollup-plugin-babel/test/samples/runtime-helpers-duplicated/main.js
new file mode 100644
index 000000000..e1cd92dd2
--- /dev/null
+++ b/packages/rollup-plugin-babel/test/samples/runtime-helpers-duplicated/main.js
@@ -0,0 +1,5 @@
+import Bar from './Bar.js';
+
+class Foo {}
+
+export { Foo, Bar };
diff --git a/packages/rollup-plugin-babel/test/test.js b/packages/rollup-plugin-babel/test/test.js
index 45def6001..07d21ae62 100644
--- a/packages/rollup-plugin-babel/test/test.js
+++ b/packages/rollup-plugin-babel/test/test.js
@@ -213,4 +213,20 @@ describe( 'rollup-plugin-babel', function () {
 			assert.equal( generated.code.indexOf( 'var typeof' ), -1, generated.code );
 		});
 	});
+
+	it( 'does not warn about duplicated helpers with transform-runtime', () => {
+		return rollup.rollup({
+			entry: 'samples/runtime-helpers-duplicated/main.js',
+			plugins: [
+				babelPlugin({
+					runtimeHelpers: true
+				})
+			],
+			onwarn ( msg ) {
+				if ( /helper is used more than once in your code/.test( msg ) ) {
+					throw new Error( 'no warning about duplicated helpers should be given' );
+				}
+			}
+		});
+	});
 });