diff --git a/types/asenv/asenv-tests.ts b/types/asenv/asenv-tests.ts
new file mode 100644
index 0000000000..0448672d10
--- /dev/null
+++ b/types/asenv/asenv-tests.ts
@@ -0,0 +1,26 @@
+import { unlessProduction, isDevelopment, isTest, isProduction, getEnv, setEnv } from 'asenv';
+import { equal, throws } from 'assert';
+
+// Test isDevelopment()
+setEnv('development');
+equal(getEnv(), 'development', 'Should return be true');
+equal(isDevelopment(), true, 'NODE_ENV should be "development"');
+equal(isTest(), false, 'NODE_ENV should be "development"');
+equal(isProduction(), false, 'NODE_ENV should be "development"');
+equal(unlessProduction(() => true), true, "Shound return true");
+
+// Test isTest()
+setEnv('test');
+equal(getEnv(), 'test', 'Should return be true');
+equal(isDevelopment(), false, 'NODE_ENV should be "test"');
+equal(isTest(), true, 'NODE_ENV should be "test"');
+equal(isProduction(), false, 'NODE_ENV should be "test"');
+equal(unlessProduction(() => true), true, "Shound return true");
+
+// Test isProduction()
+setEnv('production');
+equal(getEnv(), 'production', 'Should return be true');
+equal(isDevelopment(), false, 'NODE_ENV should be "production"');
+equal(isTest(), false, 'NODE_ENV should be "production"');
+equal(isProduction(), true, 'NODE_ENV should be "production"');
+equal(unlessProduction(() => true), false, "Shound return false");
diff --git a/types/asenv/index.d.ts b/types/asenv/index.d.ts
new file mode 100644
index 0000000000..f127664d13
--- /dev/null
+++ b/types/asenv/index.d.ts
@@ -0,0 +1,18 @@
+// Type definitions for asenv 1.1
+// Project: https://github.com/a-labo/asenv#readme
+// Definitions by: Remisery <https://github.com/remisery>
+// Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+
+/// <reference types="node" />
+
+export function getEnv(): string;
+
+export function isDevelopment(): boolean;
+
+export function isProduction(): boolean;
+
+export function isTest(): boolean;
+
+export function setEnv(env: string): void;
+
+export function unlessProduction(handle: () => any): any;
diff --git a/types/asenv/tsconfig.json b/types/asenv/tsconfig.json
new file mode 100644
index 0000000000..129dd1caf0
--- /dev/null
+++ b/types/asenv/tsconfig.json
@@ -0,0 +1,22 @@
+{
+    "compilerOptions": {
+        "module": "commonjs",
+        "lib": [
+            "es6"
+        ],
+        "noImplicitAny": true,
+        "noImplicitThis": true,
+        "strictNullChecks": true,
+        "baseUrl": "../",
+        "typeRoots": [
+            "../"
+        ],
+        "types": [],
+        "noEmit": true,
+        "forceConsistentCasingInFileNames": true
+    },
+    "files": [
+        "index.d.ts",
+        "asenv-tests.ts"
+    ]
+}
diff --git a/types/asenv/tslint.json b/types/asenv/tslint.json
new file mode 100644
index 0000000000..f93cf8562a
--- /dev/null
+++ b/types/asenv/tslint.json
@@ -0,0 +1,3 @@
+{
+    "extends": "dtslint/dt.json"
+}