diff --git a/remove_duplicates.rb b/remove_duplicates.rb
new file mode 100644
index 0000000..e440c24
--- /dev/null
+++ b/remove_duplicates.rb
@@ -0,0 +1,10 @@
+def remove_dups xs
+  _xs = {}
+  xs.reduce([]) do |uniques, x|
+    uniques << x unless _xs[x]
+    _xs[x] = true
+    uniques
+  end
+end
+
+remove_dups(["a", "b", "b", "c", "C"]) # => ["a", "b", "c", "C"]