diff --git a/lib/rdoc/options.rb b/lib/rdoc/options.rb
index 13c1abae0a..13b7ba5c6c 100644
--- a/lib/rdoc/options.rb
+++ b/lib/rdoc/options.rb
@@ -338,8 +338,9 @@ class RDoc::Options
 
   attr_reader :visibility
 
-  def initialize # :nodoc:
+  def initialize loaded_options = nil # :nodoc:
     init_ivars
+    override loaded_options if loaded_options
   end
 
   def init_ivars # :nodoc:
@@ -417,6 +418,37 @@ def yaml_initialize tag, map # :nodoc:
     init_with map
   end
 
+  def override map # :nodoc:
+    if map.has_key?('encoding')
+      encoding = map['encoding']
+      @encoding = encoding ? Encoding.find(encoding) : encoding
+    end
+
+    @charset        = map['charset']        if map.has_key?('charset')
+    @exclude        = map['exclude']        if map.has_key?('exclude')
+    @generator_name = map['generator_name'] if map.has_key?('generator_name')
+    @hyperlink_all  = map['hyperlink_all']  if map.has_key?('hyperlink_all')
+    @line_numbers   = map['line_numbers']   if map.has_key?('line_numbers')
+    @locale_name    = map['locale_name']    if map.has_key?('locale_name')
+    @locale_dir     = map['locale_dir']     if map.has_key?('locale_dir')
+    @main_page      = map['main_page']      if map.has_key?('main_page')
+    @markup         = map['markup']         if map.has_key?('markup')
+    @op_dir         = map['op_dir']         if map.has_key?('op_dir')
+    @show_hash      = map['show_hash']      if map.has_key?('show_hash')
+    @tab_width      = map['tab_width']      if map.has_key?('tab_width')
+    @template_dir   = map['template_dir']   if map.has_key?('template_dir')
+    @title          = map['title']          if map.has_key?('title')
+    @visibility     = map['visibility']     if map.has_key?('visibility')
+    @webcvs         = map['webcvs']         if map.has_key?('webcvs')
+
+    if map.has_key?('rdoc_include')
+      @rdoc_include = sanitize_path map['rdoc_include']
+    end
+    if map.has_key?('static_path')
+      @static_path  = sanitize_path map['static_path']
+    end
+  end
+
   def == other # :nodoc:
     self.class === other and
       @encoding       == other.encoding       and
diff --git a/lib/rdoc/rdoc.rb b/lib/rdoc/rdoc.rb
index 93e764c462..df04646f3c 100644
--- a/lib/rdoc/rdoc.rb
+++ b/lib/rdoc/rdoc.rb
@@ -166,8 +166,15 @@ def load_options
     rescue Psych::SyntaxError
     end
 
+    return RDoc::Options.new if options == false # Allow empty file.
+
     raise RDoc::Error, "#{options_file} is not a valid rdoc options file" unless
-      RDoc::Options === options
+      RDoc::Options === options or Hash === options
+
+    if Hash === options
+      # Override the default values with the contents of YAML file.
+      options = RDoc::Options.new options
+    end
 
     options
   end
diff --git a/test/rdoc/test_rdoc_rdoc.rb b/test/rdoc/test_rdoc_rdoc.rb
index f7d9b8659f..3910dd4656 100644
--- a/test/rdoc/test_rdoc_rdoc.rb
+++ b/test/rdoc/test_rdoc_rdoc.rb
@@ -133,6 +133,29 @@ def test_load_options_invalid
     end
   end
 
+  def test_load_options_empty_file
+    temp_dir do
+      File.open '.rdoc_options', 'w' do |io|
+      end
+
+      options = @rdoc.load_options
+
+      assert_equal 'rdoc', options.markup
+    end
+  end
+
+  def test_load_options_partial_override
+    temp_dir do
+      File.open '.rdoc_options', 'w' do |io|
+        io.write "markup: Markdown"
+      end
+
+      options = @rdoc.load_options
+
+      assert_equal 'Markdown', options.markup
+    end
+  end
+
   def load_options_no_file
     temp_dir do
       options = @rdoc.load_options