diff --git a/hamming.rb b/hamming.rb
new file mode 100644
index 0000000..e15e271
--- /dev/null
+++ b/hamming.rb
@@ -0,0 +1,18 @@
+class Hamming
+
+  def self.compute(x, y, distance=0)
+    raise (ArgumentError) if x.length != y.length
+    return distance if x.length == 0
+
+    if x[0] == y[0]
+      x = x[1..-1]
+      y = y[1..-1]
+      Hamming.compute(x, y, distance)
+    else
+      distance = distance + 1
+      x = x[1..-1]
+      y = y[1..-1]
+      Hamming.compute(x, y, distance)
+    end
+  end
+end