diff --git a/hamming.rb b/hamming.rb
new file mode 100644
index 0000000..5ca5371
--- /dev/null
+++ b/hamming.rb
@@ -0,0 +1,18 @@
+class Hamming
+  def self.compute(strand_1, strand_2, distance = 0)
+    raise ArgumentError if strand_1.length != strand_2.length
+
+    return distance if strand_1.length == 0
+
+    unless strand_1[0] == strand_2[0]
+      distance += 1
+    end
+
+    unless strand_1.length == 1
+      return Hamming.compute(strand_1[1..-1], strand_2[1..-1], distance)
+    end
+
+    return distance
+
+  end
+end