diff --git a/README.rst b/README.rst
index ea1c7466c..06bae5fde 100644
--- a/README.rst
+++ b/README.rst
@@ -712,6 +712,8 @@ For an enumeration type:
     value ? value.split(',') : []
    end
 
+The processed value will be available in ``@api_params``.
+
 ============
  Validators
 ============
diff --git a/lib/apipie/validator.rb b/lib/apipie/validator.rb
index 3eda6020f..97bb34e3c 100644
--- a/lib/apipie/validator.rb
+++ b/lib/apipie/validator.rb
@@ -398,7 +398,7 @@ def self.validate(value)
     class BooleanValidator < BaseValidator
 
       def validate(value)
-        %w[true false 1 0].include?(value.to_s)
+        %w[true false 1 0].include?(value.to_s.downcase)
       end
 
       def self.build(param_description, argument, options, block)
@@ -406,6 +406,10 @@ def self.build(param_description, argument, options, block)
           self.new(param_description)
         end
       end
+      
+      def process_value(value)
+        %w[true 1].include?(value.to_s.downcase)
+      end
 
       def expected_type
         'boolean'