diff --git a/CHANGELOG.md b/CHANGELOG.md
index c0e158714..c222065d9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -27,6 +27,9 @@
   * Add possibility to give a block to `collection_radio` and `collection_check_boxes`,
     to generate custom label and input structure. It is used internally with the :nested
     option for `:boolean_style`, and is useful to allow some more customization if required.
+  * Do not generate hidden check box field when using nested boolean style, as it is considered
+    invalid markup in HTML5. This will only work in Rails > 3.2.1 (not released at this time).
+    More info in [#215](https://github.com/plataformatec/simple_form/issues/215)
 
 ### deprecation
   * Deprecate the `translate` configuration in favor of `translate_labels`
diff --git a/lib/simple_form/inputs/boolean_input.rb b/lib/simple_form/inputs/boolean_input.rb
index cec5bc25a..b8efc17c3 100644
--- a/lib/simple_form/inputs/boolean_input.rb
+++ b/lib/simple_form/inputs/boolean_input.rb
@@ -2,14 +2,14 @@ module SimpleForm
   module Inputs
     class BooleanInput < Base
       def input
-        @builder.check_box(attribute_name, input_html_options)
+        build_check_box
       end
 
       def label_input
         if options[:label] == false
           input
         elsif nested_boolean_style?
-          @builder.label(label_target, label_html_options) { input + label_text }
+          @builder.label(label_target, label_html_options) { build_check_box(nil) + label_text }
         else
           input + label
         end
@@ -17,6 +17,13 @@ def label_input
 
       private
 
+      # Build a checkbox tag using default unchecked value. This allows us to
+      # reuse the method for nested boolean style, but with nil unchecked value,
+      # which won't generate the hidden checkbox (only in Rails > 3.2.1).
+      def build_check_box(unchecked_value='0')
+        @builder.check_box(attribute_name, input_html_options, '1', unchecked_value)
+      end
+
       # Booleans are not required by default because in most of the cases
       # it makes no sense marking them as required. The only exception is
       # Terms of Use usually presented at most sites sign up screen.
diff --git a/lib/simple_form/inputs/collection_check_boxes_input.rb b/lib/simple_form/inputs/collection_check_boxes_input.rb
index 575712a8b..1a1c686bb 100644
--- a/lib/simple_form/inputs/collection_check_boxes_input.rb
+++ b/lib/simple_form/inputs/collection_check_boxes_input.rb
@@ -10,7 +10,7 @@ def has_required?
       end
 
       def nested_boolean_style_item_tag(value, html_options)
-        @builder.check_box(attribute_name, html_options, value)
+        @builder.check_box(attribute_name, html_options, value, nil)
       end
     end
   end