diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb
index 4c51d3f3eedcd5fb83251e94d551670d0cad04c3..e4218a1a1c84bd7830614bd8b1fbae415464e64d 100755
--- a/activerecord/lib/active_record/base.rb
+++ b/activerecord/lib/active_record/base.rb
@@ -1187,7 +1187,7 @@ def undecorated_table_name(class_name = base_class.name)
         # It's even possible to use all the additional parameters to find. For example, the full interface for find_all_by_amount
         # is actually find_all_by_amount(amount, options).
         def method_missing(method_id, *arguments)
-          if match = /find_(all_by|by)_([_a-zA-Z]\w*)/.match(method_id.to_s)
+          if match = /^find_(all_by|by)_([_a-zA-Z]\w*)$/.match(method_id.to_s)
             finder, deprecated_finder = determine_finder(match), determine_deprecated_finder(match)
 
             attribute_names = extract_attribute_names_from_match(match)
@@ -1219,7 +1219,7 @@ def method_missing(method_id, *arguments)
                   send(deprecated_finder, sanitize_sql(attributes), *arguments[attribute_names.length..-1])
                 end
             end
-          elsif match = /find_or_(initialize|create)_by_([_a-zA-Z]\w*)/.match(method_id.to_s)
+          elsif match = /^find_or_(initialize|create)_by_([_a-zA-Z]\w*)$/.match(method_id.to_s)
             instantiator = determine_instantiator(match)
             attribute_names = extract_attribute_names_from_match(match)
             super unless all_attributes_exists?(attribute_names)
diff --git a/activerecord/test/finder_test.rb b/activerecord/test/finder_test.rb
index cf2dfcbb2406667d40044bbef4e5a57c30455a88..d31d859b4405d1e8c13ab3e996f80037575907a2 100644
--- a/activerecord/test/finder_test.rb
+++ b/activerecord/test/finder_test.rb
@@ -293,6 +293,13 @@ def test_find_by_one_attribute_with_several_options
   def test_find_by_one_missing_attribute
     assert_raises(NoMethodError) { Topic.find_by_undertitle("The First Topic!") }
   end
+  
+  def test_find_by_invalid_method_syntax
+    assert_raises(NoMethodError) { Topic.fail_to_find_by_title("The First Topic") }
+    assert_raises(NoMethodError) { Topic.find_by_title?("The First Topic") }
+    assert_raises(NoMethodError) { Topic.fail_to_find_or_create_by_title("Nonexistent Title") }
+    assert_raises(NoMethodError) { Topic.find_or_create_by_title?("Nonexistent Title") }
+  end
 
   def test_find_by_two_attributes
     assert_equal topics(:first), Topic.find_by_title_and_author_name("The First Topic", "David")