diff --git a/activerecord/CHANGELOG b/activerecord/CHANGELOG
index 4c58664a19..3d7b814daa 100644
--- a/activerecord/CHANGELOG
+++ b/activerecord/CHANGELOG
@@ -1,5 +1,7 @@
 *Rails 3.1.0 (unreleased)*
 
+* Active Record's dynamic finder will now show a deprecation warning if you passing in less number of arguments than what you call in method signature. This behavior will raise ArgumentError in the next version of Rails [Prem Sichanugrist]
+
 * Deprecated the AssociationCollection constant. CollectionProxy is now the appropriate constant
   to use, though be warned that this is not really a public API.
 
diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb
index 83c9d37140..c7e35029bd 100644
--- a/activerecord/lib/active_record/base.rb
+++ b/activerecord/lib/active_record/base.rb
@@ -23,6 +23,7 @@ require 'active_support/core_ext/module/delegation'
 require 'active_support/core_ext/module/introspection'
 require 'active_support/core_ext/object/duplicable'
 require 'active_support/core_ext/object/blank'
+require 'active_support/deprecation'
 require 'arel'
 require 'active_record/errors'
 require 'active_record/log_subscriber'
@@ -1056,6 +1057,13 @@ module ActiveRecord #:nodoc:
           if match = DynamicFinderMatch.match(method_id)
             attribute_names = match.attribute_names
             super unless all_attributes_exists?(attribute_names)
+            if arguments.size < attribute_names.size
+              ActiveSupport::Deprecation.warn(
+                "Calling dynamic finder with less number of arguments than the number of attributes in " \
+                "method name is deprecated and will raise an ArguementError in the next version of Rails. " \
+                "Please passing `nil' to the argument you want it to be nil."
+              )
+            end
             if match.finder?
               options = arguments.extract_options!
               relation = options.any? ? scoped(options) : scoped
@@ -1066,6 +1074,13 @@ module ActiveRecord #:nodoc:
           elsif match = DynamicScopeMatch.match(method_id)
             attribute_names = match.attribute_names
             super unless all_attributes_exists?(attribute_names)
+            if arguments.size < attribute_names.size
+              ActiveSupport::Deprecation.warn(
+                "Calling dynamic scope with less number of arguments than the number of attributes in " \
+                "method name is deprecated and will raise an ArguementError in the next version of Rails. " \
+                "Please passing `nil' to the argument you want it to be nil."
+              )
+            end
             if match.scope?
               self.class_eval <<-METHOD, __FILE__, __LINE__ + 1
                 def self.#{method_id}(*args)                                    # def self.scoped_by_user_name_and_password(*args)
diff --git a/activerecord/test/cases/finder_test.rb b/activerecord/test/cases/finder_test.rb
index 3d2a03d2b9..528ee0ce0a 100644
--- a/activerecord/test/cases/finder_test.rb
+++ b/activerecord/test/cases/finder_test.rb
@@ -666,6 +666,10 @@ class FinderTest < ActiveRecord::TestCase
     assert_nil Topic.find_by_title_and_author_name("The First Topic", "Mary")
   end
 
+  def test_find_by_two_attributes_but_passing_only_one
+    assert_deprecated { Topic.find_by_title_and_author_name("The First Topic") }
+  end
+
   def test_find_last_by_one_attribute
     assert_equal Topic.last, Topic.find_last_by_title(Topic.last.title)
     assert_nil Topic.find_last_by_title("A title with no matches")
@@ -859,6 +863,10 @@ class FinderTest < ActiveRecord::TestCase
     assert !sig38.persisted?
   end
 
+  def test_find_or_initialize_from_two_attributes_but_passing_only_one
+    assert_deprecated { Topic.find_or_initialize_by_title_and_author_name("Another topic") }
+  end
+
   def test_find_or_initialize_from_one_aggregate_attribute
     new_customer = Customer.find_or_initialize_by_balance(Money.new(123))
     assert_equal 123, new_customer.balance.amount
diff --git a/activerecord/test/cases/named_scope_test.rb b/activerecord/test/cases/named_scope_test.rb
index 34188e4915..0cc73e0409 100644
--- a/activerecord/test/cases/named_scope_test.rb
+++ b/activerecord/test/cases/named_scope_test.rb
@@ -489,6 +489,17 @@ end
 class DynamicScopeTest < ActiveRecord::TestCase
   fixtures :posts
 
+  def setup
+    # Ensure we start with a clean model with no generated class method
+    Post.methods.select{ |c| c =~ /scoped_by_/ }.each do |method_name|
+      Post.class_eval <<-RUBY
+        class << self
+          remove_method :#{method_name}
+        end
+      RUBY
+    end
+  end
+
   def test_dynamic_scope
     assert_equal Post.scoped_by_author_id(1).find(1), Post.find(1)
     assert_equal Post.scoped_by_author_id_and_title(1, "Welcome to the weblog").first, Post.find(:first, :conditions => { :author_id => 1, :title => "Welcome to the weblog"})
@@ -499,4 +510,8 @@ class DynamicScopeTest < ActiveRecord::TestCase
     Developer.scoped_by_created_at(nil)
     assert_present Developer.methods.grep(/scoped_by_created_at/)
   end
+
+  def test_dynamic_scope_with_less_number_of_arguments
+    assert_deprecated { Post.scoped_by_author_id_and_title(1) }
+  end
 end