diff --git a/examples/info.rb b/examples/info.rb
index a727bfb..c6a986e 100644
--- a/examples/info.rb
+++ b/examples/info.rb
@@ -23,7 +23,7 @@ p db.collection_names
 p db.collections_info
 
 # Index information
-db.create_index('test', 'index_name', ['a'])
+db.create_index('test', 'a')
 p db.index_information('test')
 
 # Destroy the collection
diff --git a/examples/queries.rb b/examples/queries.rb
index ecdfcfe..06eb5cf 100644
--- a/examples/queries.rb
+++ b/examples/queries.rb
@@ -59,7 +59,7 @@ pp coll.find('a' => /[1|2]/).explain()
 # collection, in which case they will be used with all queries, or they can be
 # specified per query, in which case that hint overrides the hint associated
 # with the collection if any.
-coll.create_index('test_a_index', 'a')
+coll.create_index('a')
 coll.hint = 'a'
 
 # You will see a different explanation now that the hint is in place
diff --git a/lib/mongo.rb b/lib/mongo.rb
index 35bf938..6bf1356 100644
--- a/lib/mongo.rb
+++ b/lib/mongo.rb
@@ -10,3 +10,10 @@ require 'mongo/db'
 require 'mongo/cursor'
 require 'mongo/collection'
 require 'mongo/admin'
+
+module XGen
+  module Mongo
+    ASCENDING = 1
+    DESCENDING = -1
+  end
+end
diff --git a/lib/mongo/collection.rb b/lib/mongo/collection.rb
index af1c90f..3d741fa 100644
--- a/lib/mongo/collection.rb
+++ b/lib/mongo/collection.rb
@@ -70,7 +70,7 @@ module XGen
           h = options.dup
           h[:limit] = 1
           cursor = find(selector, h)
-          cursor.next_object    # don't need to explicitly close b/c of limit 
+          cursor.next_object    # don't need to explicitly close b/c of limit
         end
 
         # Insert +objects+, which are hashes. "<<" is aliased to this method.
@@ -113,11 +113,12 @@ module XGen
           @db.modify_in_db(@name, selector, modifier_obj)
         end
 
-        # Create a new index named +index_name+. +fields+ should be an array
-        # of field names.
-        def create_index(name, *fields)
-          fields = *fields if fields.kind_of?(Array) && fields.length == 1
-          @db.create_index(@name, name, fields)
+        # Create a new index. +field_or_spec+
+        # should be either a single field name or a Array of [field name,
+        # direction] pairs. Directions should be specified as
+        # XGen::Mongo::ASCENDING or XGen::Mongo::DESCENDING.
+        def create_index(field_or_spec)
+          @db.create_index(@name, field_or_spec)
         end
 
         # Drop index +name+.
diff --git a/lib/mongo/db.rb b/lib/mongo/db.rb
index ba4d13d..6fa7329 100644
--- a/lib/mongo/db.rb
+++ b/lib/mongo/db.rb
@@ -305,7 +305,7 @@ module XGen
         def send_message(msg)
           send_to_db(MsgMessage.new(msg))
         end
-        
+
         # Returns a Cursor over the query results.
         #
         # Note that the query gets sent lazily; the cursor calls
@@ -401,17 +401,28 @@ module XGen
           }
         end
 
-        # Create a new index on +collection_name+ named +index_name+. +fields+
-        # should be an array of field names. Normally called by
-        # Collection#create_index.
-        def create_index(collection_name, index_name, fields)
-          sel = {:name => index_name, :ns => full_coll_name(collection_name)}
-          field_h = {}
-          fields.each { |f| field_h[f] = 1 }
-          sel[:key] = field_h
+        # Create a new index on +collection_name+. +field_or_spec+
+        # should be either a single field name or a Array of [field name,
+        # direction] pairs. Directions should be specified as
+        # XGen::Mongo::ASCENDING or XGen::Mongo::DESCENDING. Normally called
+        # by Collection#create_index.
+        def create_index(collection_name, field_or_spec)
+          field_h = OrderedHash.new
+          if field_or_spec.is_a? String
+            field_h[field_or_spec] = 1
+          else
+            field_or_spec.each { |f| field_h[f[0]] = f[1] }
+          end
+          name = gen_index_name(field_h)
+          sel = {
+            :name => name,
+            :ns => full_coll_name(collection_name),
+            :key => field_h
+          }
           @semaphore.synchronize {
             send_to_db(InsertMessage.new(@name, SYSTEM_INDEX_COLLECTION, sel))
           }
+          name
         end
 
         # Insert +objects+ into +collection_name+. Normally called by
@@ -471,6 +482,13 @@ module XGen
           Digest::MD5.hexdigest("#{username}:mongo:#{plaintext}")
         end
 
+        def gen_index_name(spec)
+          temp = []
+          spec.each_pair { |field, direction|
+            temp = temp.push("#{field}_#{direction}")
+          }
+          return temp.join("_")
+        end
       end
     end
   end
diff --git a/lib/mongo/gridfs/grid_store.rb b/lib/mongo/gridfs/grid_store.rb
index e4958a1..75a3673 100644
--- a/lib/mongo/gridfs/grid_store.rb
+++ b/lib/mongo/gridfs/grid_store.rb
@@ -157,7 +157,7 @@ module XGen
             @curr_chunk = nth_chunk(0)
             @position = 0
           when 'w'
-            chunk_collection.create_index("chunk_index", ['files_id', 'n'])
+            chunk_collection.create_index([['files_id', XGen::Mongo::ASCENDING], ['n', XGen::Mongo::ASCENDING]])
             delete_chunks
             @curr_chunk = Chunk.new(self, 'n' => 0)
             @content_type = options[:content_type] if options[:content_type]
@@ -165,7 +165,7 @@ module XGen
             @metadata = options[:metadata] if options[:metadata]
             @position = 0
           when 'w+'
-            chunk_collection.create_index("chunk_index", ['files_id', 'n'])
+            chunk_collection.create_index([['files_id', XGen::Mongo::ASCENDING], ['n', XGen::Mongo::ASCENDING]])
             @curr_chunk = nth_chunk(last_chunk_number) || Chunk.new(self, 'n' => 0) # might be empty
             @curr_chunk.pos = @curr_chunk.data.length if @curr_chunk
             @metadata = options[:metadata] if options[:metadata]
diff --git a/tests/test_db_api.rb b/tests/test_db_api.rb
index 545b7fd..0231b45 100644
--- a/tests/test_db_api.rb
+++ b/tests/test_db_api.rb
@@ -4,7 +4,7 @@ require 'test/unit'
 
 # NOTE: assumes Mongo is running
 class DBAPITest < Test::Unit::TestCase
-
+  include XGen::Mongo
   include XGen::Mongo::Driver
 
   @@db = Mongo.new(ENV['MONGO_RUBY_DRIVER_HOST'] || 'localhost',
@@ -275,28 +275,30 @@ class DBAPITest < Test::Unit::TestCase
   end
 
   def test_index_information
-    @@db.create_index(@@coll.name, 'index_name', ['a'])
+    name = @@db.create_index(@@coll.name, 'a')
     list = @@db.index_information(@@coll.name)
     assert_equal 1, list.length
 
     info = list[0]
-    assert_equal 'index_name', info[:name]
+    assert_equal name, 'a_1'
+    assert_equal name, info[:name]
     assert_equal 1, info[:keys]['a']
   ensure
-    @@db.drop_index(@@coll.name, 'index_name')
+    @@db.drop_index(@@coll.name, name)
   end
 
   def test_multiple_index_cols
-    @@db.create_index(@@coll.name, 'index_name', ['a', 'b', 'c'])
+    name = @@db.create_index(@@coll.name, [['a', DESCENDING], ['b', ASCENDING], ['c', DESCENDING]])
     list = @@db.index_information(@@coll.name)
     assert_equal 1, list.length
 
     info = list[0]
-    assert_equal 'index_name', info[:name]
+    assert_equal name, 'a_-1_b_1_c_-1'
+    assert_equal name, info[:name]
     keys = info[:keys].keys
     assert_equal ['a', 'b', 'c'], keys.sort
   ensure
-    @@db.drop_index(@@coll.name, 'index_name')
+    @@db.drop_index(@@coll.name, name)
   end
 
   def test_array
@@ -403,7 +405,7 @@ class DBAPITest < Test::Unit::TestCase
   end
 
   def test_hint
-    @@coll.create_index('test_a_index', 'a')
+    name = @@coll.create_index('a')
     begin
       assert_nil @@coll.hint
       assert_equal 1, @@coll.find({'a' => 1}, :hint => 'a').to_a.size
@@ -426,7 +428,7 @@ class DBAPITest < Test::Unit::TestCase
       assert_nil @@coll.hint
       assert_equal 1, @@coll.find('a' => 1).to_a.size
     ensure
-      @@coll.drop_index('test_a_index')
+      @@coll.drop_index(name)
     end
   end