diff --git a/README.md b/README.md
index 5767258..a583a6c 100644
--- a/README.md
+++ b/README.md
@@ -30,22 +30,27 @@ var newObject = changeCaseObject.camelCase(myObject);
 All methods are available under the `changeCaseObject` object after the module has been required.
 
 ### .camelCase
-Conerts all object keys into camel case.  
+Converts all object keys into camel case.  
 `hello_world -> helloWorld`
 
 ### .snakeCase
-Conerts all object keys into snake case.  
+Converts all object keys into snake case.  
 `helloWorld -> hello_world`
 
 ### .paramCase
-Conerts all object keys into param case.  
+Converts all object keys into param case.  
 `helloWorld -> hello-world`
 
+### .constantCase
+Converts all object keys into constant case.  
+`helloWorld -> HELLO_WORLD`
+
 Shorthand methods are also available:
 ```
 .camelCase -> .camel
 .snakeCase -> .snake
 .paramCase -> .param
+.constantCase -> .constant
 ```
 
 ## Code Guideline
diff --git a/index.js b/index.js
index 53b57ad..cbcc8b2 100644
--- a/index.js
+++ b/index.js
@@ -1,6 +1,7 @@
 var camelCase = require('camel-case');
 var snakeCase = require('snake-case');
 var paramCase = require('param-case');
+var constantCase = require('constant-case').constantCase;
 
 var changeKeys = function changeKeys(transformer, obj) {
   var objectKeys;
@@ -56,4 +57,12 @@ changeCaseObject.param = changeCaseObject.paramCase = function paramCaseObject(o
   return changeKeys(paramCase, obj);
 };
 
+changeCaseObject.constant = changeCaseObject.constantCase = function constantCaseObject(obj) {
+  if (typeof obj === 'string') {
+    return constantCase(obj);
+  }
+
+  return changeKeys(constantCase, obj);
+};
+
 module.exports = changeCaseObject;
diff --git a/package.json b/package.json
index afc2176..b969008 100644
--- a/package.json
+++ b/package.json
@@ -30,6 +30,7 @@
   "homepage": "https://github.com/BinaryThumb/change-case-object#readme",
   "dependencies": {
     "camel-case": "^1.2.0",
+    "constant-case": "^3.0.3",
     "param-case": "^1.1.1",
     "snake-case": "^1.1.1"
   },
diff --git a/test/index.js b/test/index.js
index 002f377..8f50830 100644
--- a/test/index.js
+++ b/test/index.js
@@ -293,4 +293,101 @@ describe('change-case-object', function () {
     expect(changeCaseObject.snakeCase(Infinity)).to.equal(Infinity);
     expect(changeCaseObject.snakeCase(NaN)).to.a('number');
   });
+
+  it('constantCase', function () {
+    var initialObj = {
+      'helloWorld': 'test',
+    };
+
+    var fixtureObj = {
+      'HELLO_WORLD': 'test',
+    };
+
+    expect(changeCaseObject.constantCase(initialObj)).to.deep.equal(fixtureObj);
+  });
+
+  it('constantCase (special characters)', function () {
+    var initialObj = {
+      'helloWorld': 'n#mä!%ads$§a',
+    };
+
+    var fixtureObj = {
+      'HELLO_WORLD': 'n#mä!%ads$§a',
+    };
+    expect(changeCaseObject.constantCase(initialObj)).to.deep.equal(fixtureObj);
+  });
+
+  it('constantCase (Array of Object)', function () {
+    var initialArrObj = [
+      { 'helloWorld': 'test' },
+      { isActive: true },
+      { 'is-Active': true },
+    ];
+
+    var fixtureArrObj = [
+      { 'HELLO_WORLD': 'test' },
+      { IS_ACTIVE: true },
+      { IS_ACTIVE: true },
+    ];
+
+    expect(changeCaseObject.constantCase(initialArrObj)).to.deep.equal(fixtureArrObj);
+  });
+
+  it('constantCase (Array of string)', function () {
+    var initialArrStr = ['isActive', 'isBlocked'];
+
+    var fixtureArrStr = ['IS_ACTIVE', 'IS_BLOCKED'];
+
+    expect(changeCaseObject.constantCase(initialArrStr)).to.deep.equal(fixtureArrStr);
+  });
+
+  it('constantCase (Primitive - string)', function () {
+    var initialPrimitive = 'isActive';
+
+    var fixturePrimitive = 'IS_ACTIVE';
+
+    expect(changeCaseObject.constantCase(initialPrimitive)).to.deep.equal(fixturePrimitive);
+  });
+
+  it('constantCase (Primitive - number)', function () {
+    var initialPrimitive = 42;
+
+    var fixturePrimitive = 42;
+
+    expect(changeCaseObject.constantCase(initialPrimitive)).to.deep.equal(fixturePrimitive);
+  });
+
+  it('constantCase (Primitive - bool)', function () {
+    var initialPrimitive = true;
+
+    var fixturePrimitive = true;
+
+    expect(changeCaseObject.constantCase(initialPrimitive)).to.deep.equal(fixturePrimitive);
+  });
+
+  it('constantCase (deep)', function () {
+    var initialObj = {
+      'helloWorld': {
+        'helloThere': 'name',
+        'myName': 'someone',
+      },
+    };
+
+    var fixtureObj = {
+      'HELLO_WORLD': {
+        'HELLO_THERE': 'name',
+        'MY_NAME': 'someone',
+      },
+    };
+
+    expect(changeCaseObject.constantCase(initialObj)).to.deep.equal(fixtureObj);
+  });
+
+  it('constantCase (edge cases)', function () {
+    expect(changeCaseObject.constantCase(null)).to.equal(null);
+    expect(changeCaseObject.constantCase({})).to.a('object');
+    expect(changeCaseObject.constantCase([])).to.a('array');
+    expect(changeCaseObject.constantCase(Infinity)).to.equal(Infinity);
+    expect(changeCaseObject.constantCase(NaN)).to.a('number');
+  });
 });