diff --git a/README.md b/README.md
index f7c12f8..6c5256c 100644
--- a/README.md
+++ b/README.md
@@ -65,7 +65,7 @@ If the _value_ is omitted, an outbound header with an expired date is used to de
 
 If the _options_ object is provided, it will be used to generate the outbound cookie header as follows:
 
-* `maxAge`: a number representing the milliseconds from `Date.now()` for expiry
+* `maxAge`: a number representing the milliseconds from `Date.now()` for expiry. If this and `expires` are both set this will take precedence. This value will be converted to seconds before being added to the Set-Cookie header
 * `expires`: a `Date` object indicating the cookie's expiration date (expires at the end of session by default).
 * `path`: a string indicating the path of the cookie (`/` by default).
 * `domain`: a string indicating the domain of the cookie (no default).
diff --git a/index.js b/index.js
index 9c468ae..f98ff8a 100644
--- a/index.js
+++ b/index.js
@@ -164,6 +164,7 @@ Cookie.prototype.toHeader = function() {
 
   if (this.maxAge) this.expires = new Date(Date.now() + this.maxAge);
 
+  if (this.maxAge   ) header += "; max-age=" + Math.round(this.maxAge / 1000)
   if (this.path     ) header += "; path=" + this.path
   if (this.expires  ) header += "; expires=" + this.expires.toUTCString()
   if (this.domain   ) header += "; domain=" + this.domain
diff --git a/test/test.js b/test/test.js
index 91dfb42..be82f55 100644
--- a/test/test.js
+++ b/test/test.js
@@ -297,7 +297,7 @@ describe('new Cookies(req, res, [options])', function () {
         .end(done)
       })
 
-      it('should not set the "maxAge" attribute', function (done) {
+      it('should set the "maxAge" attribute', function (done) {
         request(createServer(function (req, res, cookies) {
           cookies.set('foo', 'bar', { maxAge: 86400000 })
           res.end()
@@ -305,7 +305,18 @@ describe('new Cookies(req, res, [options])', function () {
         .get('/')
         .expect(200)
         .expect(shouldSetCookieWithAttribute('foo', 'expires'))
-        .expect(shouldSetCookieWithoutAttribute('foo', 'maxAge'))
+        .expect(shouldSetCookieWithAttribute('foo', 'max-age'))
+        .end(done)
+      })
+
+      it('should convert the "maxAge" attribute to seconds', function (done) {
+        request(createServer(function (req, res, cookies) {
+          cookies.set('foo', 'bar', { maxAge: 86400001 })
+          res.end()
+        }))
+        .get('/')
+        .expect(200)
+        .expect(shouldSetCookieWithAttributeAndValue('foo', 'max-age', '86400'))
         .end(done)
       })
     })