diff --git a/lib/multipart/post/composite_read_io.rb b/lib/multipart/post/composite_read_io.rb
index 44704b7..6773e39 100644
--- a/lib/multipart/post/composite_read_io.rb
+++ b/lib/multipart/post/composite_read_io.rb
@@ -33,8 +33,26 @@ def initialize(*ios)
         @index = 0
       end
 
+      # Close all the underyling IOs.
+      def close
+        @ios.each do |io|
+          io.close if io.respond_to?(:close)
+        end
+
+        @ios = nil
+        @index = 0
+      end
+
+      def closed?
+        @ios.nil?
+      end
+
       # Read from IOs in order until `length` bytes have been received.
       def read(length = nil, outbuf = nil)
+        if @ios.nil?
+          raise IOError, "CompositeReadIO is closed!"
+        end
+
         got_result = false
         outbuf = outbuf ? outbuf.replace("") : String.new
 
diff --git a/spec/multipart/post/composite_read_io_spec.rb b/spec/multipart/post/composite_read_io_spec.rb
index 1bd2cc2..9b38eda 100644
--- a/spec/multipart/post/composite_read_io_spec.rb
+++ b/spec/multipart/post/composite_read_io_spec.rb
@@ -12,6 +12,11 @@
 MULTIBYTE = File.dirname(__FILE__) + '/../../fixtures/multibyte.txt'
 
 RSpec.shared_context "composite io" do
+  it "can close all the ios" do
+    subject.close
+    expect(subject.closed?).to be_truthy
+  end
+  
   it "test_full_read_from_several_ios" do
     expect(subject.read).to be == 'the quick brown fox'
   end