diff --git a/index.js b/index.js
index 23bd82b071..828abf5519 100644
--- a/index.js
+++ b/index.js
@@ -359,6 +359,19 @@ exports.ecsign = function (msgHash, privateKey) {
   return ret
 }
 
+/**
+ * Returns the keccak-256 hash of `message`, prefixed with the header used by the `eth_sign` RPC call.
+ * The output of this function can be fed into `ecsign` to produce the same signature as the `eth_sign`
+ * call for a given `message`, or fed to `ecrecover` along with a signature to recover the public key
+ * used to produce the signature.
+ * @param message
+ * @returns {Buffer} hash
+ */
+exports.hashPersonalMessage = function (message) {
+  var prefix = exports.toBuffer('\u0019Ethereum Signed Message:\n' + message.length.toString())
+  return exports.sha3(Buffer.concat([prefix, message]))
+}
+
 /**
  * ECDSA public key recovery from signature
  * @param {Buffer} msgHash
diff --git a/test/index.js b/test/index.js
index b3351889ec..b449204964 100644
--- a/test/index.js
+++ b/test/index.js
@@ -479,6 +479,13 @@ describe('ecrecover', function () {
   })
 })
 
+describe('hashPersonalMessage', function () {
+  it('should produce a deterministic hash', function () {
+    var h = ethUtils.hashPersonalMessage(Buffer.from('Hello world'))
+    assert.deepEqual(h, Buffer.from('8144a6fa26be252b86456491fbcd43c1de7e022241845ffea1c3df066f7cfede', 'hex'))
+  })
+})
+
 describe('isValidSignature', function () {
   it('should fail on an invalid signature (shorter r))', function () {
     var r = Buffer.from('99e71a99cb2270b8cac5254f9e99b6210c6c10224a1579cf389ef88b20a1ab', 'hex')