diff --git a/package.json b/package.json
index 3c1c25e7e..83b1919d9 100644
--- a/package.json
+++ b/package.json
@@ -73,5 +73,8 @@
     "posttest": "[ -z \"$TRAVIS\" ] || codecov",
     "codecov": "codecov",
     "bench": "BENCHMARK=true npm run test"
+  },
+  "dependencies": {
+    "murmurhash-js": "^1.0.0"
   }
 }
diff --git a/src/Jss.js b/src/Jss.js
index 7486cbadb..da01167e7 100644
--- a/src/Jss.js
+++ b/src/Jss.js
@@ -1,7 +1,7 @@
+import hash from 'murmurhash-js/murmurhash3_gc'
 import StyleSheet from './StyleSheet'
 import PluginsRegistry from './PluginsRegistry'
 import SheetsRegistry from './SheetsRegistry'
-import {uid} from './utils'
 import createRule from './createRule'
 import findRenderer from './findRenderer'
 
@@ -11,11 +11,11 @@ import findRenderer from './findRenderer'
  * @api public
  */
 export default class Jss {
-  constructor() {
+  constructor(options = {}) {
     this.sheets = new SheetsRegistry()
     this.plugins = new PluginsRegistry()
-    this.uid = uid
     this.version = process.env.VERSION
+    this.hash = options.hash || hash
   }
 
   /**
@@ -24,8 +24,8 @@ export default class Jss {
    * @see Jss
    * @api public
    */
-  create() {
-    return new Jss()
+  create(options) {
+    return new Jss(options)
   }
 
   /**
diff --git a/src/StyleSheet.js b/src/StyleSheet.js
index 637823676..c196bc1d4 100644
--- a/src/StyleSheet.js
+++ b/src/StyleSheet.js
@@ -125,13 +125,13 @@ export default class StyleSheet {
    */
   toString(options) {
     const {rules} = this
-    const stringified = Object.create(null)
+    const stringified = []
     let str = ''
     for (const name in rules) {
       const rule = rules[name]
       // We have the same rule referenced twice if using named rules.
       // By name and by selector.
-      if (stringified[rule.id]) {
+      if (stringified.indexOf(rule) !== -1) {
         continue
       }
 
@@ -146,7 +146,7 @@ export default class StyleSheet {
       if (str) str += '\n'
 
       str += rule.toString(options)
-      stringified[rule.id] = true
+      stringified.push(rule)
     }
     return str
   }
diff --git a/src/rules/ConditionalRule.js b/src/rules/ConditionalRule.js
index 34b53da65..4ca3c7033 100644
--- a/src/rules/ConditionalRule.js
+++ b/src/rules/ConditionalRule.js
@@ -1,4 +1,4 @@
-import {isEmptyObject, uid} from '../utils'
+import {isEmptyObject} from '../utils'
 
 /**
  * Conditional rule for @media, @supports
@@ -7,7 +7,6 @@ import {isEmptyObject, uid} from '../utils'
  */
 export default class ConditionalRule {
   constructor(selector, styles, options) {
-    this.id = uid.get()
     this.type = 'conditional'
     this.selector = selector
     this.options = options
diff --git a/src/rules/FontFaceRule.js b/src/rules/FontFaceRule.js
index 07ae7b59c..c3f25485d 100644
--- a/src/rules/FontFaceRule.js
+++ b/src/rules/FontFaceRule.js
@@ -1,4 +1,4 @@
-import {uid, toCSS} from '../utils'
+import {toCSS} from '../utils'
 
 /**
  * Font-face rules.
@@ -7,7 +7,6 @@ import {uid, toCSS} from '../utils'
  */
 export default class Rule {
   constructor(selector, style, options) {
-    this.id = uid.get()
     this.type = 'font-face'
     this.options = options
     this.selector = selector
diff --git a/src/rules/KeyframeRule.js b/src/rules/KeyframeRule.js
index 10d07ae85..4d5540ff1 100644
--- a/src/rules/KeyframeRule.js
+++ b/src/rules/KeyframeRule.js
@@ -1,5 +1,3 @@
-import {uid} from '../utils'
-
 /**
  * Keyframe rule.
  *
@@ -7,7 +5,6 @@ import {uid} from '../utils'
  */
 export default class KeyframeRule {
   constructor(selector, frames, options) {
-    this.id = uid.get()
     this.type = 'keyframe'
     this.selector = selector
     this.options = options
diff --git a/src/rules/Rule.js b/src/rules/Rule.js
index 905719a0c..5480b3013 100644
--- a/src/rules/Rule.js
+++ b/src/rules/Rule.js
@@ -1,4 +1,6 @@
-import {clone, uid, toCSS, findClassNames} from '../utils'
+import {toCSS, findClassNames} from '../utils'
+const {parse, stringify} = JSON
+
 
 /**
  * Regular rules.
@@ -7,18 +9,23 @@ import {clone, uid, toCSS, findClassNames} from '../utils'
  */
 export default class Rule {
   constructor(selector, style, options) {
-    this.id = uid.get()
+    // We expect style to be plain object.
+    // To avoid original style object mutations, we clone it and hash it
+    // along the way.
+    // It is also the fastetst way.
+    // http://jsperf.com/lodash-deepclone-vs-jquery-extend-deep/6
+    const styleStr = stringify(style)
+    const hash = options.jss.hash(styleStr)
+    this.style = parse(styleStr)
     this.type = 'regular'
     this.options = options
     this.selectorText = selector || ''
     this.className = options.className || ''
     this.originalStyle = style
-    // We expect style to be plain object.
-    this.style = clone(style)
     if (options.named) {
       this.name = selector
       if (!this.className) {
-        this.className = this.name ? `${this.name}--${this.id}` : this.id
+        this.className = this.name ? `${this.name}-${hash}` : hash
       }
       this.selectorText = `.${this.className}`
     }
diff --git a/src/rules/SimpleRule.js b/src/rules/SimpleRule.js
index 6fed7629d..2dfc3a692 100644
--- a/src/rules/SimpleRule.js
+++ b/src/rules/SimpleRule.js
@@ -1,5 +1,3 @@
-import {uid} from '../utils'
-
 /**
  * Rule like @charset, @import, @namespace.
  *
@@ -7,7 +5,6 @@ import {uid} from '../utils'
  */
 export default class SimpleRule {
   constructor(name, value, options) {
-    this.id = uid.get()
     this.type = 'simple'
     this.name = name
     this.value = value
diff --git a/src/utils.js b/src/utils.js
index 901853f64..451b68af6 100644
--- a/src/utils.js
+++ b/src/utils.js
@@ -1,19 +1,3 @@
-const stringify = JSON.stringify
-const parse = JSON.parse
-
-/**
- * Deeply clone object using serialization.
- * Expects object to be plain and without cyclic dependencies.
- *
- * http://jsperf.com/lodash-deepclone-vs-jquery-extend-deep/6
- *
- * @type {Object} obj
- * @return {Object}
- */
-export function clone(obj) {
-  return parse(stringify(obj))
-}
-
 /**
  * Determine whether an object is empty or not.
  * More performant than a `Object.keys(obj).length > 0`
@@ -27,41 +11,6 @@ export function isEmptyObject(obj) {
   return true
 }
 
-/**
- * Simple very fast UID generation based on a global counter.
- */
-export const uid = (() => {
-  const globalReference = typeof window == 'undefined' ? global : window
-  const namespace = '__JSS_VERSION_COUNTER__'
-  if (globalReference[namespace] == null) globalReference[namespace] = 0
-
-  // In case we have more than one jss version.
-  const versionCounter = globalReference[namespace]++
-  let ruleCounter = 0
-
-  /**
-   * Returns a uid.
-   * Ensures uniqueness if more than 1 jss version is used.
-   *
-   * @api public
-   * @return {String}
-   */
-  function get() {
-    return `jss-${versionCounter}-${ruleCounter++}`
-  }
-
-  /**
-   * Resets the counter.
-   *
-   * @api public
-   */
-  function reset() {
-    ruleCounter = 0
-  }
-
-  return {get, reset}
-})()
-
 /**
  * Indent a string.
  *
diff --git a/tests/functional/sheet.js b/tests/functional/sheet.js
index 17c03c027..16bdc7446 100644
--- a/tests/functional/sheet.js
+++ b/tests/functional/sheet.js
@@ -181,7 +181,7 @@ describe('Functional: sheet', () => {
     })
 
     it('should render correct CSS', () => {
-      expect(getCss(style)).to.be('.a--jss-0-0 { float: left; }')
+      expect(getCss(style)).to.be('.a-id { float: left; }')
     })
 
     it('should register the rule', () => {
diff --git a/tests/integration/jss.js b/tests/integration/jss.js
index 5f9ebcda6..8d3fdaf6d 100644
--- a/tests/integration/jss.js
+++ b/tests/integration/jss.js
@@ -46,10 +46,10 @@ describe('Integration: jss', () => {
 
     it('should return CSS of all sheets from .sheets.toString()', () => {
       const css =
-        '.a--jss-0-0 {\n' +
+        '.a-id {\n' +
         '  color: red;\n' +
         '}\n' +
-        '.a--jss-0-1 {\n' +
+        '.a-id {\n' +
         '  color: blue;\n' +
         '}'
       expect(jss.sheets.toString()).to.be(css)
diff --git a/tests/integration/rules.js b/tests/integration/rules.js
index d8381874b..5527d0407 100644
--- a/tests/integration/rules.js
+++ b/tests/integration/rules.js
@@ -7,14 +7,10 @@ afterEach(reset)
 describe('Integration: rules', () => {
   describe('.createRule()', () => {
     it('should create a rule without args', () => {
-      let rule = jss.createRule()
-      expect(rule.type).to.be('regular')
-      expect(rule.className).to.be('jss-0-0')
-      expect(rule.selector).to.be('.jss-0-0')
-      rule = jss.createRule()
+      const rule = jss.createRule()
       expect(rule.type).to.be('regular')
-      expect(rule.className).to.be('jss-0-1')
-      expect(rule.selector).to.be('.jss-0-1')
+      expect(rule.className).to.be('id')
+      expect(rule.selector).to.be('.id')
     })
 
     it('should accept styles only', () => {
@@ -22,8 +18,8 @@ describe('Integration: rules', () => {
       const rule = jss.createRule(style)
       expect(rule.style).to.eql(style)
       expect(rule.type).to.be('regular')
-      expect(rule.className).to.be('jss-0-0')
-      expect(rule.selector).to.be('.jss-0-0')
+      expect(rule.className).to.be('id')
+      expect(rule.selector).to.be('.id')
     })
 
     it('should accept styles and options', () => {
@@ -32,8 +28,8 @@ describe('Integration: rules', () => {
       const rule = jss.createRule(style, options)
       expect(rule.style).to.eql(style)
       expect(rule.type).to.be('regular')
-      expect(rule.className).to.be('jss-0-0')
-      expect(rule.selector).to.be('.jss-0-0')
+      expect(rule.className).to.be('id')
+      expect(rule.selector).to.be('.id')
       expect(rule.options.named).to.be(true)
       expect(rule.options.jss).to.be(jss)
       expect(rule.options.something).to.be(true)
@@ -161,7 +157,7 @@ describe('Integration: rules', () => {
         expect(rule.selector).to.be('@media print')
         expect(rule.toString()).to.be(
           '@media print {\n' +
-          '  .button--jss-0-1 {\n' +
+          '  .button-id {\n' +
           '    display: none;\n' +
           '  }\n' +
           '}'
@@ -247,7 +243,7 @@ describe('Integration: rules', () => {
       expect(rule.selector).to.be('@supports ( display: flexbox )')
       const css =
         '@supports ( display: flexbox ) {\n' +
-        '  .button--jss-0-1 {\n' +
+        '  .button-id {\n' +
         '    display: none;\n' +
         '  }\n' +
         '}'
diff --git a/tests/integration/sheet.js b/tests/integration/sheet.js
index 5da0ac13b..a312bbf78 100755
--- a/tests/integration/sheet.js
+++ b/tests/integration/sheet.js
@@ -18,9 +18,9 @@ describe('Integration: sheet', () => {
       const sheet = jss.createStyleSheet({a: {float: 'left'}})
       const rule = sheet.getRule('a')
       expect(rule).to.be.a(Rule)
-      expect(sheet.classes.a).to.be('a--jss-0-0')
-      expect(rule.className).to.be('a--jss-0-0')
-      expect(rule.selector).to.be('.a--jss-0-0')
+      expect(sheet.classes.a).to.be('a-id')
+      expect(rule.className).to.be('a-id')
+      expect(rule.selector).to.be('.a-id')
     })
 
     it('should create an unnamed sheet', () => {
@@ -38,7 +38,7 @@ describe('Integration: sheet', () => {
           a: {float: 'left'}
         }
       })
-      expect(sheet.classes.a).to.be('a--jss-0-1')
+      expect(sheet.classes.a).to.be('a-id')
     })
   })
 
@@ -46,7 +46,7 @@ describe('Integration: sheet', () => {
     it('should return a rule by name and selector from named sheet', () => {
       const sheet = jss.createStyleSheet({a: {float: 'left'}})
       expect(sheet.getRule('a')).to.be.a(Rule)
-      expect(sheet.getRule('.a--jss-0-0')).to.be.a(Rule)
+      expect(sheet.getRule('.a-id')).to.be.a(Rule)
     })
 
     it('should return a rule by selector from unnamed sheet', () => {
@@ -123,16 +123,16 @@ describe('Integration: sheet', () => {
         '@media (min-width: 1000px)': {a: {color: 'green'}}
       })
       expect(sheet.toString()).to.be(
-        '.a--jss-0-0 {\n' +
+        '.a-id {\n' +
         '  color: red;\n' +
         '}\n' +
         '@media (min-width: 1024px) {\n' +
-        '  .a--jss-0-0 {\n' +
+        '  .a-id {\n' +
         '    color: blue;\n' +
         '  }\n' +
         '}\n' +
         '@media (min-width: 1000px) {\n' +
-        '  .a--jss-0-0 {\n' +
+        '  .a-id {\n' +
         '    color: green;\n' +
         '  }\n' +
         '}'
@@ -148,10 +148,10 @@ describe('Integration: sheet', () => {
           d: {}
         })
         expect(sheet.toString()).to.be(
-          '.a--jss-0-0 {\n' +
+          '.a-id {\n' +
           '  color: red;\n' +
           '}\n' +
-          '.c--jss-0-2 {\n' +
+          '.c-id {\n' +
           '  color: green;\n' +
           '}'
         )
@@ -165,10 +165,10 @@ describe('Integration: sheet', () => {
           '@font-face': {}
         })
         expect(sheet.toString()).to.be(
-          '.a--jss-0-0 {\n' +
+          '.a-id {\n' +
           '  color: red;\n' +
           '}\n' +
-          '.c--jss-0-2 {\n' +
+          '.c-id {\n' +
           '  color: green;\n' +
           '}'
         )
@@ -180,7 +180,7 @@ describe('Integration: sheet', () => {
           '@media print': {}
         })
         expect(sheet.toString()).to.be(
-          '.a--jss-0-0 {\n' +
+          '.a-id {\n' +
           '  color: red;\n' +
           '}'
         )
diff --git a/tests/utils.js b/tests/utils.js
index 98f045d5d..3c453ff2c 100644
--- a/tests/utils.js
+++ b/tests/utils.js
@@ -38,5 +38,7 @@ export function computeStyle(className) {
 export function reset() {
   jss.plugins.registry = []
   jss.sheets.registry = []
-  jss.uid.reset()
 }
+
+// Mock the hash function.
+jss.hash = () => 'id'