diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
index 24c734c..54d54c5 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
@@ -274,7 +274,7 @@ module ActiveRecord
         column_options = {}
         column_options[:null] = null unless null.nil?
         column_options[:default] = default unless default.nil?
-        add_column_options!(column_sql, column_options) unless type.to_sym == :primary_key
+        add_column_options!(column_sql, column_options)
         column_sql
       end
       alias to_s :to_sql
@@ -318,8 +318,8 @@ module ActiveRecord
 
       # Appends a primary key definition to the table definition.
       # Can be called multiple times, but this is probably not a good idea.
-      def primary_key(name)
-        column(name, :primary_key)
+      def primary_key(name, options = {})
+        column(name, :primary_key, options)
       end
 
       # Returns a ColumnDefinition for the column with name +name+.
@@ -341,7 +341,7 @@ module ActiveRecord
       #
       # Available options are (none of these exists by default):
       # * <tt>:limit</tt> -
-      #   Requests a maximum column length. This is number of characters for <tt>:string</tt> and <tt>:text</tt> columns and number of bytes for :binary and :integer columns.
+      #   Requests a maximum column length. This is number of characters for <tt>:string</tt> and <tt>:text</tt> columns and number of bytes for :binary, :integer and :primary_key columns.
       # * <tt>:default</tt> -
       #   The column's default value. Use nil for NULL.
       # * <tt>:null</tt> -
diff --git a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
index 9300df2..a628a29 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
@@ -183,7 +183,7 @@ module ActiveRecord
       QUOTED_TRUE, QUOTED_FALSE = '1'.freeze, '0'.freeze
 
       NATIVE_DATABASE_TYPES = {
-        :primary_key => "int(11) DEFAULT NULL auto_increment PRIMARY KEY".freeze,
+        :primary_key => { :name => "DEFAULT NULL auto_increment PRIMARY KEY", :limit => 4 },
         :string      => { :name => "varchar", :limit => 255 },
         :text        => { :name => "text" },
         :integer     => { :name => "int", :limit => 4 },
@@ -524,15 +524,21 @@ module ActiveRecord
 
       # Maps logical Rails types to MySQL-specific data types.
       def type_to_sql(type, limit = nil, precision = nil, scale = nil)
-        return super unless type.to_s == 'integer'
-
-        case limit
-        when 1; 'tinyint'
-        when 2; 'smallint'
-        when 3; 'mediumint'
-        when nil, 4, 11; 'int(11)'  # compatibility with MySQL default
-        when 5..8; 'bigint'
-        else raise(ActiveRecordError, "No integer type has byte size #{limit}")
+        case type.to_s
+        when 'primary_key':
+          native = native_database_types[:primary_key]
+          return type_to_sql('integer', limit) + ' ' + native[:name]
+        when 'integer':
+          case limit
+          when 1; 'tinyint'
+          when 2; 'smallint'
+          when 3; 'mediumint'
+          when nil, 4, 11; 'int(11)'  # compatibility with MySQL default
+          when 5..8; 'bigint'
+          else raise(ActiveRecordError, "No integer type has byte size #{limit}")
+          end
+        else
+          super
         end
       end
 
diff --git a/activerecord/lib/active_record/schema_dumper.rb b/activerecord/lib/active_record/schema_dumper.rb
index 557a554..f2afe39 100644
--- a/activerecord/lib/active_record/schema_dumper.rb
+++ b/activerecord/lib/active_record/schema_dumper.rb
@@ -76,6 +76,7 @@ HEADER
       def table(table, stream)
         columns = @connection.columns(table)
         begin
+          column_specs = columns.dup
           tbl = StringIO.new
 
           if @connection.respond_to?(:pk_and_sequence_for)
@@ -84,9 +85,12 @@ HEADER
           pk ||= 'id'
 
           tbl.print "  create_table #{table.inspect}"
-          if columns.detect { |c| c.name == pk }
-            if pk != 'id'
-              tbl.print %Q(, :primary_key => "#{pk}")
+          if pkc = column_specs.detect { |c| c.name == pk }
+            if pkc.limit != @types[:primary_key][:limit]
+              tbl.print ", :id => false"
+            else
+              column_specs.delete(pkc)
+              tbl.print %Q(, :primary_key => "#{pk}") if pk != 'id'
             end
           else
             tbl.print ", :id => false"
@@ -94,20 +98,25 @@ HEADER
           tbl.print ", :force => true"
           tbl.puts " do |t|"
 
-          column_specs = columns.map do |column|
+          column_specs.map! do |column|
             raise StandardError, "Unknown type '#{column.sql_type}' for column '#{column.name}'" if @types[column.type].nil?
-            next if column.name == pk
             spec = {}
-            spec[:name]      = column.name.inspect
-            spec[:type]      = column.type.to_s
-            spec[:limit]     = column.limit.inspect if column.limit != @types[column.type][:limit] && column.type != :decimal
-            spec[:precision] = column.precision.inspect if !column.precision.nil?
-            spec[:scale]     = column.scale.inspect if !column.scale.nil?
-            spec[:null]      = 'false' if !column.null
-            spec[:default]   = default_string(column.default) if column.has_default?
+            spec[:name] = column.name.inspect
+            spec[:limit] = column.limit.inspect if column.limit != @types[column.type][:limit] && column.type != :decimal
+
+            if column.name == pk
+              spec[:type]      = 'primary_key'
+            else
+              spec[:type]      = column.type.to_s
+              spec[:precision] = column.precision.inspect if !column.precision.nil?
+              spec[:scale]     = column.scale.inspect if !column.scale.nil?
+              spec[:null]      = 'false' if !column.null
+              spec[:default]   = default_string(column.default) if column.has_default?
+            end
+
             (spec.keys - [:name, :type]).each{ |k| spec[k].insert(0, "#{k.inspect} => ")}
             spec
-          end.compact
+          end
 
           # find all migration keys used in this table
           keys = [:name, :limit, :precision, :scale, :default, :null] & column_specs.map(&:keys).flatten
@@ -176,4 +185,4 @@ HEADER
         end
       end
   end
-end
\ No newline at end of file
+end
diff --git a/activerecord/test/cases/schema_dumper_test.rb b/activerecord/test/cases/schema_dumper_test.rb
index 17e4c75..50e2d09 100644
--- a/activerecord/test/cases/schema_dumper_test.rb
+++ b/activerecord/test/cases/schema_dumper_test.rb
@@ -40,7 +40,7 @@ class SchemaDumperTest < ActiveRecord::TestCase
       next if column_set.empty?
 
       lengths = column_set.map do |column|
-        if match = column.match(/t\.(?:integer|decimal|float|datetime|timestamp|time|date|text|binary|string|boolean)\s+"/)
+        if match = column.match(/t\.(?:primary_key|integer|decimal|float|datetime|timestamp|time|date|text|binary|string|boolean)\s+"/)
           match[0].length
         end
       end
@@ -160,6 +160,13 @@ class SchemaDumperTest < ActiveRecord::TestCase
       assert_match %r(:primary_key => "movieid"), match[1], "non-standard primary key not preserved"
     end
 
+    def test_mysql_schema_dump_should_honor_primary_keys_limits
+      output = standard_dump
+      match = output.match(%r{create_table "primary_key_limit",.*?:id => false\b.*? do (.*?)\bend$}m)
+      assert_not_nil(match, output)
+      assert_match %r(t.primary_key\s+"id",\s+:limit => \d+$), match[1], "limit option not found on primary key"
+    end
+
     def test_schema_dump_includes_length_for_mysql_blob_and_text_fields
       output = standard_dump
       assert_match %r{t.binary\s+"tiny_blob",\s+:limit => 255$}, output
diff --git a/activerecord/test/schema/schema.rb b/activerecord/test/schema/schema.rb
index 9ebf1d8..d861abe 100644
--- a/activerecord/test/schema/schema.rb
+++ b/activerecord/test/schema/schema.rb
@@ -346,6 +346,10 @@ ActiveRecord::Schema.define do
     t.integer :price
   end
 
+  create_table :primary_key_limit, :force => true, :id => false do |t|
+    t.primary_key :id, :limit => 8
+  end
+
   create_table :projects, :force => true do |t|
     t.string :name
     t.string :type