diff --git a/benchmarks/cookies/validate-max-age.mjs b/benchmarks/cookies/validate-max-age.mjs
new file mode 100644
index 00000000000..019cc375d71
--- /dev/null
+++ b/benchmarks/cookies/validate-max-age.mjs
@@ -0,0 +1,12 @@
+import { bench, group, run } from 'mitata'
+import { validateCookieMaxAge } from '../../lib/web/cookies/util.js'
+
+const valid = 2000
+
+group('validateCookieMaxAge', () => {
+  bench(`valid: ${valid}`, () => {
+    return validateCookieMaxAge(valid)
+  })
+})
+
+await run()
diff --git a/lib/web/cookies/util.js b/lib/web/cookies/util.js
index d49857175a4..0aa5331ccb5 100644
--- a/lib/web/cookies/util.js
+++ b/lib/web/cookies/util.js
@@ -197,10 +197,21 @@ function toIMFDate (date) {
                        ; In practice, both expires-av and max-age-av
                        ; are limited to dates representable by the
                        ; user agent.
+ *
+ * @see https://www.rfc-editor.org/rfc/rfc6265#section-4.1.1
+ *
+ * but:
+ * If delta-seconds is less than or equal to zero (0), let expiry-time be the
+ * earliest representable date and time. Otherwise, let the expiry-time be the
+ * current date and time plus delta-seconds seconds.
+ * @see https://www.rfc-editor.org/rfc/rfc6265#section-5.2.2
+ *
+ * Any integer value is valid.
+ *
  * @param {number} maxAge
  */
 function validateCookieMaxAge (maxAge) {
-  if (maxAge < 0) {
+  if (Number.isInteger(maxAge) === false) {
     throw new Error('Invalid cookie max-age')
   }
 }
@@ -301,6 +312,7 @@ module.exports = {
   validateCookieName,
   validateCookiePath,
   validateCookieValue,
+  validateCookieMaxAge,
   toIMFDate,
   stringify,
   getHeadersList
diff --git a/test/cookie/cookies.js b/test/cookie/cookies.js
index 711f26a0351..19b8627daa4 100644
--- a/test/cookie/cookies.js
+++ b/test/cookie/cookies.js
@@ -255,7 +255,11 @@ test('Cookie Set', () => {
   } catch {
     error = true
   }
-  assert.ok(error)
+  assert.strictEqual(error, false)
+  assert.equal(
+    headers.get('Set-Cookie'),
+    'Space=Cat; Secure; HttpOnly; Max-Age=-1'
+  )
 
   headers = new Headers()
   setCookie(headers, {
diff --git a/test/cookie/validate-cookie-max-age.js b/test/cookie/validate-cookie-max-age.js
new file mode 100644
index 00000000000..c33ca5ba115
--- /dev/null
+++ b/test/cookie/validate-cookie-max-age.js
@@ -0,0 +1,37 @@
+'use strict'
+
+const { test, describe } = require('node:test')
+const { throws, strictEqual } = require('node:assert')
+
+const {
+  validateCookieMaxAge
+} = require('../../lib/web/cookies/util')
+
+describe('validateCookieMaxAge', () => {
+  test('0', () => {
+    strictEqual(validateCookieMaxAge(0), undefined)
+    strictEqual(validateCookieMaxAge(+0), undefined)
+    strictEqual(validateCookieMaxAge(-0), undefined)
+  })
+
+  test('float', () => {
+    throws(() => validateCookieMaxAge(3.15), Error('Invalid cookie max-age'))
+  })
+
+  test('integer value', () => {
+    strictEqual(validateCookieMaxAge(2), undefined)
+    strictEqual(validateCookieMaxAge(-2), undefined)
+  })
+
+  test('-Infinity', () => {
+    throws(() => validateCookieMaxAge(-Infinity), Error('Invalid cookie max-age'))
+  })
+
+  test('Infinity', () => {
+    throws(() => validateCookieMaxAge(Infinity), Error('Invalid cookie max-age'))
+  })
+
+  test('NaN', () => {
+    throws(() => validateCookieMaxAge(NaN), Error('Invalid cookie max-age'))
+  })
+})