diff --git a/lib/AWS/EC2/instances.rb b/lib/AWS/EC2/instances.rb
index 71f7653..d234a06 100644
--- a/lib/AWS/EC2/instances.rb
+++ b/lib/AWS/EC2/instances.rb
@@ -37,7 +37,7 @@ def run_instances( options = {} )
         raise ArgumentError, ":image_id must be provided" if options[:image_id].nil? || options[:image_id].empty?
         raise ArgumentError, ":min_count is not valid" unless options[:min_count].to_i > 0
         raise ArgumentError, ":max_count is not valid or must be >= :min_count" unless options[:max_count].to_i > 0 && options[:max_count].to_i >= options[:min_count].to_i
-        raise ArgumentError, ":instance_type must specify a valid instance type" unless options[:instance_type].nil? || ["t1.micro", "m1.small", "m1.large", "m1.xlarge", "m2.xlarge", "c1.medium", "c1.xlarge", "m2.2xlarge", "m2.4xlarge", "cc1.4xlarge"].include?(options[:instance_type])
+        raise ArgumentError, ":instance_type must specify a valid instance type" unless options[:instance_type].nil? || ["t1.micro", "m1.small", "m1.medium", "m1.large", "m1.xlarge", "m2.xlarge", "c1.medium", "c1.xlarge", "m2.2xlarge", "m2.4xlarge", "cc1.4xlarge"].include?(options[:instance_type])
         raise ArgumentError, ":monitoring_enabled must be 'true' or 'false'" unless options[:monitoring_enabled].nil? || [true, false].include?(options[:monitoring_enabled])
         raise ArgumentError, ":disable_api_termination must be 'true' or 'false'" unless options[:disable_api_termination].nil? || [true, false].include?(options[:disable_api_termination])
         raise ArgumentError, ":instance_initiated_shutdown_behavior must be 'stop' or 'terminate'" unless options[:instance_initiated_shutdown_behavior].nil? || ["stop", "terminate"].include?(options[:instance_initiated_shutdown_behavior])
diff --git a/lib/AWS/EC2/spot_instance_requests.rb b/lib/AWS/EC2/spot_instance_requests.rb
index 52cc1cc..8281b6e 100644
--- a/lib/AWS/EC2/spot_instance_requests.rb
+++ b/lib/AWS/EC2/spot_instance_requests.rb
@@ -37,7 +37,7 @@ def request_spot_instances( options = {} )
         raise ArgumentError, ":addressing_type has been deprecated." if options[:addressing_type]
         raise ArgumentError, ":spot_price must be provided" if options[:spot_price].nil? || options[:spot_price].empty?
         raise ArgumentError, ":base64_encoded must be 'true' or 'false'" unless [true, false].include?(options[:base64_encoded])
-        raise ArgumentError, ":instance_type must specify a valid instance type" unless options[:instance_type].nil? || ["t1.micro", "m1.small", "m1.large", "m1.xlarge", "m2.xlarge", "c1.medium", "c1.xlarge", "m2.2xlarge", "m2.4xlarge", "cc1.4xlarge"].include?(options[:instance_type])
+        raise ArgumentError, ":instance_type must specify a valid instance type" unless options[:instance_type].nil? || ["t1.micro", "m1.small", "m1.medium", "m1.large", "m1.xlarge", "m2.xlarge", "c1.medium", "c1.xlarge", "m2.2xlarge", "m2.4xlarge", "cc1.4xlarge"].include?(options[:instance_type])
 
         user_data = extract_user_data(options)
 
diff --git a/lib/AWS/EC2/spot_prices.rb b/lib/AWS/EC2/spot_prices.rb
index c0c9c7f..a62cc9f 100644
--- a/lib/AWS/EC2/spot_prices.rb
+++ b/lib/AWS/EC2/spot_prices.rb
@@ -16,7 +16,7 @@ class Base < AWS::Base
       def describe_spot_price_history( options = {} )
         raise ArgumentError, ":start_time must be a Time object" unless options[:start_time].nil? || options[:start_time].kind_of?(Time)
         raise ArgumentError, ":end_time must be a Time object" unless options[:end_time].nil? || options[:end_time].kind_of?(Time)
-        raise ArgumentError, ":instance_type must specify a valid instance type" unless options[:instance_type].nil? || ["t1.micro", "m1.small", "m1.large", "m1.xlarge", "m2.xlarge", "c1.medium", "c1.xlarge", "m2.2xlarge", "m2.4xlarge", "cc1.4xlarge", "cg1.4xlarge"].include?(options[:instance_type])
+        raise ArgumentError, ":instance_type must specify a valid instance type" unless options[:instance_type].nil? || ["t1.micro", "m1.small", "m1.medium", "m1.large", "m1.xlarge", "m2.xlarge", "c1.medium", "c1.xlarge", "m2.2xlarge", "m2.4xlarge", "cc1.4xlarge", "cg1.4xlarge"].include?(options[:instance_type])
         raise ArgumentError, ":product_description must be 'Linux/UNIX' or 'Windows'" unless options[:product_description].nil? || ["Linux/UNIX", "Windows"].include?(options[:product_description])
 
         params = {}
diff --git a/test/test_EC2_instances.rb b/test/test_EC2_instances.rb
index 2d771d4..103a47c 100644
--- a/test/test_EC2_instances.rb
+++ b/test/test_EC2_instances.rb
@@ -332,7 +332,7 @@
 
     # :instance_type
 
-    ["t1.micro", "m1.small", "m1.large", "m1.xlarge", "m2.xlarge", "c1.medium", "c1.xlarge", "m2.2xlarge", "m2.4xlarge", "cc1.4xlarge"].each do |type|
+    ["t1.micro", "m1.small", "m1.medium", "m1.large", "m1.xlarge", "m2.xlarge", "c1.medium", "c1.xlarge", "m2.2xlarge", "m2.4xlarge", "cc1.4xlarge"].each do |type|
       @ec2.stubs(:make_request).with('RunInstances', "ImageId" => "ami-60a54009", "MinCount" => '1', "MaxCount" => '1', "InstanceType" => type).
         returns stub(:body => @run_instances_response_body, :is_a? => true)
       lambda { @ec2.run_instances( :image_id => "ami-60a54009", :instance_type => type ) }.should.not.raise(AWS::ArgumentError)
diff --git a/test/test_EC2_spot_instance_requests.rb b/test/test_EC2_spot_instance_requests.rb
index c751ac0..40f6bac 100644
--- a/test/test_EC2_spot_instance_requests.rb
+++ b/test/test_EC2_spot_instance_requests.rb
@@ -108,7 +108,7 @@
   end
 
   specify "should be able to be requested with various instance sizes" do
-    ["t1.micro", "m1.small", "m1.large", "m1.xlarge", "m2.xlarge", "c1.medium", "c1.xlarge", "m2.2xlarge", "m2.4xlarge", "cc1.4xlarge"].each do |type|
+    ["t1.micro", "m1.small", "m1.medium", "m1.large", "m1.xlarge", "m2.xlarge", "c1.medium", "c1.xlarge", "m2.2xlarge", "m2.4xlarge", "cc1.4xlarge"].each do |type|
       @ec2.stubs(:make_request).with('RequestSpotInstances', {"SpotPrice"=>"0.50", 'LaunchSpecification.InstanceType' => type, 'LaunchSpecification.ImageId' => 'ami-60a54009', "InstanceCount"=>"1"}).
         returns stub(:body => @create_spot_instances_request_response_body, :is_a? => true)
       lambda { @ec2.request_spot_instances( :image_id => "ami-60a54009", :instance_type => type, :spot_price => '0.50' ) }.should.not.raise(AWS::ArgumentError)
diff --git a/test/test_EC2_spot_prices.rb b/test/test_EC2_spot_prices.rb
index ec9b63d..69404d4 100644
--- a/test/test_EC2_spot_prices.rb
+++ b/test/test_EC2_spot_prices.rb
@@ -41,7 +41,7 @@
   end
 
   specify "should be able to be requested with various instance types" do
-    ["t1.micro", "m1.small", "m1.large", "m1.xlarge", "m2.xlarge", "c1.medium", "c1.xlarge", "m2.2xlarge", "m2.4xlarge", "cc1.4xlarge", "cg1.4xlarge"].each do |type|
+    ["t1.micro", "m1.small", "m1.medium", "m1.large", "m1.xlarge", "m2.xlarge", "c1.medium", "c1.xlarge", "m2.2xlarge", "m2.4xlarge", "cc1.4xlarge", "cg1.4xlarge"].each do |type|
       @ec2.stubs(:make_request).with('DescribeSpotPriceHistory', {'InstanceType' => type}).
         returns stub(:body => @describe_spot_price_history_response_body, :is_a? => true)
       lambda { @ec2.describe_spot_price_history( :instance_type => type ) }.should.not.raise(AWS::ArgumentError)