diff --git a/src/unary.js b/src/unary.js
index c6976ea..54e4172 100644
--- a/src/unary.js
+++ b/src/unary.js
@@ -30,3 +30,20 @@ export const tan = (input) => unary(input, Math.tan);
 export const copy = (input) => unary(input, (x) => x);
 export const reciprocal = (input) => unary(input, (x) => 1 / x);
 export const sqrt = (input) => unary(input, Math.sqrt);
+export const erf = (input) => unary(input, (x) => {
+  // reference 1: https://en.wikipedia.org/wiki/Error_function
+  // reference 2: https://github.com/tensorflow/tfjs/blob/master/tfjs-backend-cpu/src/kernels/Erf.ts
+  const a1 = 0.254829592;
+  const a2 = -0.284496736;
+  const a3 = 1.421413741;
+  const a4 =-1.453152027;
+  const a5 = 1.061405429;
+  const p = 0.3275911;
+  const sign = Math.sign(x);
+  const v = Math.abs(x);
+  const t = 1.0 / (1.0 + p * v);
+  return sign *
+      (1.0 -
+          (((((a5 * t + a4) * t) + a3) * t + a2) * t + a1) * t *
+          Math.exp(-v * v));
+});
diff --git a/test/unary_test.js b/test/unary_test.js
index bef9d4e..596905f 100644
--- a/test/unary_test.js
+++ b/test/unary_test.js
@@ -141,6 +141,33 @@ describe('test unary', function() {
         [3, 2, 2, 1]);
   });
 
+  it('erf', function() {
+    // erf 1D
+    testUnary(
+        'erf',
+        [-0.25, 0.25, 0.5, 0.75, -0.4],
+        [
+          -0.2763262613535272,
+          0.2763262613535272,
+          0.5205000163047472,
+          0.7111555696366565,
+          -0.42839242346728446,
+        ],
+        [5]);
+    // erf 2D
+    testUnary(
+        'erf',
+        [
+          0.2, 0.3,
+          0.4, 0.5,
+        ],
+        [
+          0.22270245785831588, 0.32862668272901174,
+          0.42839242346728446, 0.5205000163047472,
+        ],
+        [2, 2]);
+  });
+
   it('exp', function() {
     testUnary('exp', [-1, 0, 1], [0.36787944117144233, 1, 2.718281828459045], [3]);
     testUnary(