diff --git a/activeresource/CHANGELOG b/activeresource/CHANGELOG
index 1f30c14f6f..70bc5675e2 100644
--- a/activeresource/CHANGELOG
+++ b/activeresource/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* Interpret 422 Unprocessable Entity as ResourceInvalid.  #7097 [dkubb]
+
 * Mega documentation patches. #7025, #7069 [rwdaigle]
 
 * Base.exists?(id, options) and Base#exists? check whether the resource is found.  #6970 [rwdaigle]
diff --git a/activeresource/README b/activeresource/README
index a657e3a471..702ab7efed 100644
--- a/activeresource/README
+++ b/activeresource/README
@@ -118,7 +118,7 @@ as the id of the ARes object.
   # when save is called on a new Person object.  An empty response is
   # is expected with a 'Location' header value:
   #
-  # Response (200): Location: http://api.people.com:3000/people/2
+  # Response (201): Location: http://api.people.com:3000/people/2
   #
   ryan = Person.new(:first => 'Ryan')
   ryan.new?  #=> true
@@ -184,7 +184,7 @@ exception.
 ==== Validation errors
 
 Creating and updating resources can lead to validation errors - i.e. 'First name cannot be empty' etc...
-These types of errors are denoted in the response by a response code of 400 and the xml representation
+These types of errors are denoted in the response by a response code of 422 and the xml representation
 of the validation errors.  The save operation will then fail (with a 'false' return value) and the
 validation errors can be accessed on the resource in question.
 
@@ -194,7 +194,7 @@ validation errors can be accessed on the resource in question.
   #
   # is requested with invalid values, the expected response is:
   #
-  # Response (400):
+  # Response (422):
   # <errors><error>First cannot be empty</error></errors>
   #
   ryan = Person.find(1)
@@ -210,13 +210,13 @@ If the underlying Http request for an ARes operation results in an error respons
 exception will be raised.  The following Http response codes will result in these exceptions:
 
    200 - 399: Valid response, no exception
-   400: ActiveResource::ResourceInvalid (automatically caught by ARes validation)
    404: ActiveResource::ResourceNotFound
    409: ActiveResource::ResourceConflict
+   422: ActiveResource::ResourceInvalid (rescued by save as validation errors)
    401 - 499: ActiveResource::ClientError
    500 - 599: ActiveResource::ServerError
 
-   
+
 === Authentication
 
 Many REST apis will require username/password authentication, usually in the form of
@@ -227,4 +227,4 @@ in the Url of the ARes site:
      self.site = "http://ryan:password@api.people.com:3000/"
    end
 
-For obvious reasons it is best if such services are available over https.
\ No newline at end of file
+For obvious reasons it is best if such services are available over https.
diff --git a/activeresource/lib/active_resource/connection.rb b/activeresource/lib/active_resource/connection.rb
index 528a7cc678..8e25ec5eb6 100644
--- a/activeresource/lib/active_resource/connection.rb
+++ b/activeresource/lib/active_resource/connection.rb
@@ -90,10 +90,10 @@ module ActiveResource
             response
           when 404
             raise(ResourceNotFound.new(response))
-          when 400
-            raise(ResourceInvalid.new(response))
           when 409
             raise(ResourceConflict.new(response))
+          when 422
+            raise(ResourceInvalid.new(response))
           when 401...500
             raise(ClientError.new(response))
           when 500...600
diff --git a/activeresource/test/base_errors_test.rb b/activeresource/test/base_errors_test.rb
index c6b840ebe1..3527eb2353 100644
--- a/activeresource/test/base_errors_test.rb
+++ b/activeresource/test/base_errors_test.rb
@@ -4,7 +4,7 @@ require "fixtures/person"
 class BaseErrorsTest < Test::Unit::TestCase
   def setup
     ActiveResource::HttpMock.respond_to do |mock|
-      mock.post "/people.xml", {}, "<?xml version=\"1.0\" encoding=\"UTF-8\"?><errors><error>Age can't be blank</error><error>Name can't be blank</error><error>Name must start with a letter</error><error>Person quota full for today.</error></errors>", 400
+      mock.post "/people.xml", {}, "<?xml version=\"1.0\" encoding=\"UTF-8\"?><errors><error>Age can't be blank</error><error>Name can't be blank</error><error>Name must start with a letter</error><error>Person quota full for today.</error></errors>", 422
     end
     @person = Person.new(:name => '', :age => '')
     assert_equal @person.save, false
diff --git a/activeresource/test/connection_test.rb b/activeresource/test/connection_test.rb
index 99f0b8de89..8fcbf089de 100644
--- a/activeresource/test/connection_test.rb
+++ b/activeresource/test/connection_test.rb
@@ -36,12 +36,12 @@ class ConnectionTest < Test::Unit::TestCase
     # 404 is a missing resource.
     assert_response_raises ActiveResource::ResourceNotFound, 404
 
-    # 400 is a validation error
-    assert_response_raises ActiveResource::ResourceInvalid, 400
-
     # 409 is an optimistic locking error
     assert_response_raises ActiveResource::ResourceConflict, 409
 
+    # 422 is a validation error
+    assert_response_raises ActiveResource::ResourceInvalid, 422
+
     # 4xx are client errors.
     [401, 499].each do |code|
       assert_response_raises ActiveResource::ClientError, code