diff --git a/lib/GetFilenameFromUrl.js b/lib/GetFilenameFromUrl.js
index 5c6527a95..d74297972 100644
--- a/lib/GetFilenameFromUrl.js
+++ b/lib/GetFilenameFromUrl.js
@@ -33,4 +33,31 @@ function getFilenameFromUrl(publicPath, outputPath, url) {
 
 }
 
-module.exports = getFilenameFromUrl;
+// support for multi-compiler configuration
+// see: https://github.com/webpack/webpack-dev-server/issues/641
+function getPaths(publicPath, compiler, url) {
+	var compilers = compiler && compiler.compilers;
+	if(Array.isArray(compilers)) {
+		var compilerPublicPath;
+		for(var i = 0; i < compilers.length; i++) {
+			compilerPublicPath = compilers[i].options
+				&& compilers[i].options.output
+				&& compilers[i].options.output.publicPath;
+			if(url.indexOf(compilerPublicPath) === 0) {
+				return {
+					publicPath: compilerPublicPath,
+					outputPath: compilers[i].outputPath
+				};
+			}
+		}
+	}
+	return {
+		publicPath: publicPath,
+		outputPath: compiler.outputPath
+	};
+}
+
+module.exports = function(publicPath, compiler, url) {
+	var paths = getPaths(publicPath, compiler, url);
+	return getFilenameFromUrl(paths.publicPath, paths.outputPath, url);
+};
diff --git a/middleware.js b/middleware.js
index dedcb1996..cdb089f86 100644
--- a/middleware.js
+++ b/middleware.js
@@ -36,7 +36,7 @@ module.exports = function(compiler, options) {
 			return goNext();
 		}
 
-		var filename = getFilenameFromUrl(context.options.publicPath, context.compiler.outputPath, req.url);
+		var filename = getFilenameFromUrl(context.options.publicPath, context.compiler, req.url);
 		if(filename === false) return goNext();
 
 
@@ -75,7 +75,7 @@ module.exports = function(compiler, options) {
 		}
 	}
 
-	webpackDevMiddleware.getFilenameFromUrl = getFilenameFromUrl.bind(this, context.options.publicPath, context.compiler.outputPath);
+	webpackDevMiddleware.getFilenameFromUrl = getFilenameFromUrl.bind(this, context.options.publicPath, context.compiler);
 	webpackDevMiddleware.waitUntilValid = shared.waitUntilValid;
 	webpackDevMiddleware.invalidate = shared.invalidate;
 	webpackDevMiddleware.close = shared.close;
diff --git a/test/GetFilenameFromUrl.test.js b/test/GetFilenameFromUrl.test.js
index d38b56e4c..173061a2a 100644
--- a/test/GetFilenameFromUrl.test.js
+++ b/test/GetFilenameFromUrl.test.js
@@ -2,7 +2,7 @@ var should = require("should");
 var getFilenameFromUrl = require("../lib/GetFilenameFromUrl");
 
 function testUrl(options) {
-	var url = getFilenameFromUrl(options.publicPath, options.outputPath, options.url);
+	var url = getFilenameFromUrl(options.publicPath, options, options.url);
 	should.strictEqual(url, options.expected);
 }
 
@@ -33,47 +33,47 @@ describe("GetFilenameFromUrl", function() {
 				url: "/test.html?foo=bar",
 				outputPath: "/",
 				publicPath: "/",
-				expected: "/test.html",
+				expected: "/test.html"
 			}, {
 				url: "/a.js",
 				outputPath: "/dist",
 				publicPath: "/",
-				expected: "/dist/a.js",
+				expected: "/dist/a.js"
 			}, {
 				url: "/b.js",
 				outputPath: "/",
 				publicPath: undefined,
-				expected: "/b.js",
+				expected: "/b.js"
 			}, {
 				url: "/c.js",
 				outputPath: undefined,
 				publicPath: undefined,
-				expected: "/c.js",
+				expected: "/c.js"
 			}, {
 				url: "/more/complex/path.js",
 				outputPath: "/a",
 				publicPath: "/",
-				expected: "/a/more/complex/path.js",
+				expected: "/a/more/complex/path.js"
 			}, {
 				url: "/more/complex/path.js",
 				outputPath: "/a",
 				publicPath: "/complex",
-				expected: false,
+				expected: false
 			}, {
 				url: "c.js",
 				outputPath: "/dist",
 				publicPath: "/",
-				expected: false, // publicPath is not in url, so it should fail
+				expected: false // publicPath is not in url, so it should fail
 			}, {
 				url: "/bar/",
 				outputPath: "/foo",
 				publicPath: "/bar/",
-				expected: "/foo",
+				expected: "/foo"
 			}, {
 				url: "/bar/",
 				outputPath: "/",
 				publicPath: "http://localhost/foo/",
-				expected: false,
+				expected: false
 			}, {
 				url: "http://test.domain/test/sample.js",
 				outputPath: "/",
@@ -94,7 +94,70 @@ describe("GetFilenameFromUrl", function() {
 				outputPath: "/",
 				publicPath: "/",
 				expected: "/pathname with spaces.js"
-			},
+			}, {
+				url: "/js/sample.js",
+				compilers: [
+					{ outputPath: "/foo", options: { output: { publicPath: "/js/" } } },
+					{ outputPath: "/bar", options: { output: { publicPath: "/css/" } } }
+				],
+				outputPath: "/root",
+				publicPath: "/",
+				expected: "/foo/sample.js"
+			}, {
+				url: "/css/sample.css",
+				compilers: [
+					{ outputPath: "/foo", options: { output: { publicPath: "/js/" } } },
+					{ outputPath: "/bar", options: { output: { publicPath: "/css/" } } }
+				],
+				outputPath: "/root",
+				publicPath: "/",
+				expected: "/bar/sample.css"
+			}, {
+				url: "/other/sample.txt",
+				compilers: [
+					{ outputPath: "/foo", options: { output: { publicPath: "/js/" } } },
+					{ outputPath: "/bar", options: { output: { publicPath: "/css/" } } }
+				],
+				outputPath: "/root",
+				publicPath: "/",
+				expected: "/root/other/sample.txt"
+			}, {
+				url: "/js/sample.js",
+				compilers: [
+					{ outputPath: "/foo", options: { output: { publicPath: "/js/" } } },
+					{ outputPath: "/bar", options: { output: { publicPath: "/css/" } } }
+				],
+				outputPath: "/root",
+				publicPath: "/test/",
+				expected: "/foo/sample.js"
+			}, {
+				url: "/css/sample.css",
+				compilers: [
+					{ outputPath: "/foo", options: { output: { publicPath: "/js/" } } },
+					{ outputPath: "/bar", options: { output: { publicPath: "/css/" } } }
+				],
+				outputPath: "/root",
+				publicPath: "/test/",
+				expected: "/bar/sample.css"
+			}, {
+				url: "/other/sample.txt",
+				compilers: [
+					{ outputPath: "/foo", options: { output: { publicPath: "/js/" } } },
+					{ outputPath: "/bar", options: { output: { publicPath: "/css/" } } }
+				],
+				outputPath: "/root",
+				publicPath: "/test/",
+				expected: false
+			}, {
+				url: "/test/sample.txt",
+				compilers: [
+					{ outputPath: "/foo", options: { output: { publicPath: "/js/" } } },
+					{ outputPath: "/bar", options: { output: { publicPath: "/css/" } } }
+				],
+				outputPath: "/root",
+				publicPath: "/test/",
+				expected: "/root/sample.txt"
+			}
 		];
 		results.forEach(testUrl);
 	});
diff --git a/test/Server.test.js b/test/Server.test.js
index c4aecfbb3..07039afa8 100644
--- a/test/Server.test.js
+++ b/test/Server.test.js
@@ -153,7 +153,7 @@ describe("Server", function() {
 			var instance = middleware(compiler, {
 				stats: "errors-only",
 				quiet: true,
-				publicPath: "/",
+				publicPath: "/"
 			});
 			app.use(instance);
 			listen = listenShorthand(done);
@@ -161,9 +161,9 @@ describe("Server", function() {
 		after(close);
 
 		it("request to both bundle files", function(done) {
-			request(app).get("/foo.js")
+			request(app).get("/js1/foo.js")
 			.expect(200, function() {
-				request(app).get("/bar.js")
+				request(app).get("/js2/bar.js")
 				.expect(200, done);
 			});
 		});
diff --git a/test/fixtures/server-test/webpack.array.config.js b/test/fixtures/server-test/webpack.array.config.js
index 59f2ca27b..d6e7db06e 100644
--- a/test/fixtures/server-test/webpack.array.config.js
+++ b/test/fixtures/server-test/webpack.array.config.js
@@ -3,13 +3,15 @@ module.exports = [{
 	entry: "./foo.js",
 	output: {
 		filename: "foo.js",
-		path: "/"
+		path: "/js1",
+		publicPath: "/js1/"
 	}
 }, {
 	context: __dirname,
 	entry: "./bar.js",
 	output: {
 		filename: "bar.js",
-		path: "/"
+		path: "/js2",
+		publicPath: "/js2/"
 	}
 }];