diff --git a/lib/sinatra/base.rb b/lib/sinatra/base.rb
index 043efbc9..00fb4a4f 100644
--- a/lib/sinatra/base.rb
+++ b/lib/sinatra/base.rb
@@ -868,13 +868,16 @@ module Sinatra
     end
 
     # Enable string or symbol key access to the nested params hash.
-    def indifferent_params(params)
-      params = indifferent_hash.merge(params)
-      params.each do |key, value|
-        case value
-          when Hash  then params[key] = indifferent_params(value)
-          when Array then params[key] = value.map { |item| indifferent_params(item) }
-        end
+    def indifferent_params(object)
+      case object
+      when Hash
+        new_hash = indifferent_hash
+        object.each { |key, value| new_hash[key] = indifferent_params(value) }
+        new_hash
+      when Array
+        object.map { |item| indifferent_params(item) }
+      else
+        object
       end
     end
 
diff --git a/test/routing_test.rb b/test/routing_test.rb
index 4b544f17..89180587 100644
--- a/test/routing_test.rb
+++ b/test/routing_test.rb
@@ -372,6 +372,18 @@ class RoutingTest < Test::Unit::TestCase
     assert_equal 'well, alright', body
   end
 
+  it "supports arrays within params" do
+    mock_app {
+      get '/foo' do
+        assert_equal ['A', 'B'], params['bar']
+        'looks good'
+      end
+    }
+    get '/foo?bar[]=A&bar[]=B'
+    assert ok?
+    assert_equal 'looks good', body
+  end
+
   it "supports deeply nested params" do
     expected_params = {
       "emacs" => {