diff --git a/lib/zero/response.rb b/lib/zero/response.rb
index 15fb8c7..264c9ae 100644
--- a/lib/zero/response.rb
+++ b/lib/zero/response.rb
@@ -4,7 +4,8 @@ module Zero
   #
   class Response
     attr_reader :status
-    attr_accessor :header, :body
+    attr_reader :body
+    attr_accessor :header
 
     # Constructor
     # Sets default status code to 200.
@@ -24,6 +25,23 @@ module Zero
       @status = status.to_i
     end
 
+    # set the body to a new value
+    #
+    # Use this function to set the body to a new value. It can either be an
+    # Object responding to `#each` per rack convention or a kind of string.
+    #
+    # @param content [#each, String] the content of the body
+    def body=(content)
+      content = [content] if content.kind_of?(String)
+
+      unless content.respond_to?(:each) then
+        raise ArgumentError.new(
+          "invalid body! Should be kind of String or respond to #each!")
+      end
+
+      @body = content
+    end
+
     # Returns the data of the response as an array:
     # [status, header, body]
     # to be usable by any webserver.
diff --git a/spec/unit/zero/response/body_spec.rb b/spec/unit/zero/response/body_spec.rb
index b70af04..0a40659 100644
--- a/spec/unit/zero/response/body_spec.rb
+++ b/spec/unit/zero/response/body_spec.rb
@@ -9,4 +9,31 @@ describe Zero::Response do
       subject.body.should eq([])
     end
   end
+
+  describe '#body=' do
+    let(:string) { "new body" }
+    let(:array)  { ["new body"] }
+    let(:object_with_each) { {:a => "b" } }
+    let(:invalid_object)   { 12345 }
+
+    it "creates an array body for strings" do
+      subject.body = string
+      expect(subject.body).to eq(array)
+    end
+
+    it "sets the body to the array" do
+      subject.body = array
+      expect(subject.body).to be(array)
+    end
+
+    it "sets an object as string when responding to #each" do
+      subject.body = object_with_each
+      expect(subject.body).to be(object_with_each)
+    end
+
+    it "raises an argument error for invalid input" do
+      expect{subject.body = invalid_object}.to raise_error(
+                                                  ArgumentError, /invalid body/)
+    end
+  end
 end