diff --git a/Javascript/Numbers/greatesCommonDivisor.js b/Javascript/Numbers/greatesCommonDivisor.js
new file mode 100644
index 0000000..fde6e58
--- /dev/null
+++ b/Javascript/Numbers/greatesCommonDivisor.js
@@ -0,0 +1,10 @@
+// gdc method returns the greatest common divisor between two numbers
+const gcd = (a, b) => {
+  // firstly, check that input is a number or not.
+  if (typeof a !== 'number' || typeof b !== 'number') {
+    return 'invalid argument, not a number.'
+  }
+  return b === 0 ? a : gcd(b, a % b)
+}
+
+console.log(gcd(10, 15))