diff --git a/lib/mongo/collection.rb b/lib/mongo/collection.rb
index 3cb3a71..03375a0 100644
--- a/lib/mongo/collection.rb
+++ b/lib/mongo/collection.rb
@@ -415,100 +415,55 @@ module Mongo
     # @param [String, Code] finalize :: optional. a JavaScript function that receives and modifies
     #              each of the resultant grouped objects. Available only when group is run
     #              with command set to true.
-    # @param [Boolean] command if true, run the group as a command instead of in an
-    #   eval. Note: Running group as eval has been DEPRECATED.
+    # @param [Nil] deprecated this param in a placeholder for a deprecated param. It will be removed
+    #   in the next release.
     #
     # @return [Array] the grouped items.
-    def group(key, condition, initial, reduce, command=false, finalize=nil)
+    def group(key, condition, initial, reduce, finalize=nil, deprecated=nil)
 
-      if command
+      # Warn of changed API post eval deprecation.
+      if finalize == true || finalize == false || deprecated
+        warn "The API for Collection#group has changed. 'Finalize' is now the fifth parameter, " +
+          "since it's no longer necessary to specify whether #group is run as a command. " +
+          "See http://api.mongodb.org/ruby/current/Mongo/Collection.html#group-instance_method for details."
+      end
 
-        reduce = Code.new(reduce) unless reduce.is_a?(Code)
+      reduce = Code.new(reduce) unless reduce.is_a?(Code)
 
-        group_command = {
-          "group" => {
-            "ns"      => @name,
-            "$reduce" => reduce,
-            "cond"    => condition,
-            "initial" => initial
-          }
+      group_command = {
+        "group" => {
+          "ns"      => @name,
+          "$reduce" => reduce,
+          "cond"    => condition,
+          "initial" => initial
         }
+      }
 
-        unless key.nil?
-          if key.is_a? Array
-            key_type = "key"
-            key_value = {}
-            key.each { |k| key_value[k] = 1 }
-          else
-            key_type  = "$keyf"
-            key_value = key.is_a?(Code) ? key : Code.new(key)
-          end
-
-          group_command["group"][key_type] = key_value
-        end
-
-        # only add finalize if specified
-        if finalize
-          finalize = Code.new(finalize) unless finalize.is_a?(Code)
-          group_command['group']['finalize'] = finalize
-        end
-
-        result = @db.command group_command
-
-        if result["ok"] == 1
-          return result["retval"]
+      unless key.nil?
+        if key.is_a? Array
+          key_type = "key"
+          key_value = {}
+          key.each { |k| key_value[k] = 1 }
         else
-          raise OperationFailure, "group command failed: #{result['errmsg']}"
+          key_type  = "$keyf"
+          key_value = key.is_a?(Code) ? key : Code.new(key)
         end
 
+        group_command["group"][key_type] = key_value
+      end
+
+      # only add finalize if specified
+      if finalize
+        finalize = Code.new(finalize) unless finalize.is_a?(Code)
+        group_command['group']['finalize'] = finalize
+      end
+
+      result = @db.command group_command
+
+      if result["ok"] == 1
+        result["retval"]
       else
-
-        warn "Collection#group must now be run as a command; you can do this by passing 'true' as the command argument."
-
-        raise OperationFailure, ":finalize can be specified only when " +
-          "group is run as a command (set command param to true)" if finalize
-
-        raise OperationFailure, "key must be an array of fields to group by. If you want to pass a key function, 
-          run group as a command by passing 'true' as the command argument." unless key.is_a? Array || key.nil?
-
-        case reduce
-        when Code
-          scope = reduce.scope
-        else
-          scope = {}
-        end
-        scope.merge!({
-                       "ns" => @name,
-                       "keys" => key,
-                       "condition" => condition,
-                       "initial" => initial })
-
-      group_function = <<EOS
-function () {
-    var c = db[ns].find(condition);
-    var map = new Map();
-    var reduce_function = #{reduce};
-    while (c.hasNext()) {
-        var obj = c.next();
-
-        var key = {};
-        for (var i = 0; i < keys.length; i++) {
-            var k = keys[i];
-            key[k] = obj[k];
-        }
-
-        var aggObj = map.get(key);
-        if (aggObj == null) {
-            var newObj = Object.extend({}, key);
-            aggObj = Object.extend(newObj, initial);
-            map.put(key, aggObj);
-        }
-        reduce_function(obj, aggObj);
-    }
-    return {"result": map.values()};
-}
-EOS
-        @db.eval(Code.new(group_function, scope))["result"]
+        raise OperationFailure, "group command failed: #{result['errmsg']}"
       end
     end
 
diff --git a/test/collection_test.rb b/test/collection_test.rb
index 7e5440e..272e498 100644
--- a/test/collection_test.rb
+++ b/test/collection_test.rb
@@ -437,15 +437,9 @@ class TestCollection < Test::Unit::TestCase
       assert_equal 4, @@test.group([], {}, @initial, Code.new(@reduce_function, {"inc_value" => 2}))[0]["count"]
     end
 
-    should "group results using command form" do
-      assert_equal 1, @@test.group([], {}, @initial, Code.new(@reduce_function, {"inc_value" => 0.5}), true)[0]["count"]
-      assert_equal 2, @@test.group([], {}, @initial, Code.new(@reduce_function, {"inc_value" => 1}), true)[0]["count"]
-      assert_equal 4, @@test.group([], {}, @initial, Code.new(@reduce_function, {"inc_value" => 2}), true)[0]["count"]
-    end
-
     should "finalize grouped results" do
       @finalize = "function(doc) {doc.f = doc.count + 200; }"
-      assert_equal 202, @@test.group([], {}, @initial, Code.new(@reduce_function, {"inc_value" => 1}), true, @finalize)[0]["f"]
+      assert_equal 202, @@test.group([], {}, @initial, Code.new(@reduce_function, {"inc_value" => 1}), @finalize)[0]["f"]
     end
   end
 
@@ -463,16 +457,10 @@ class TestCollection < Test::Unit::TestCase
     end
 
     should "group results" do
-      results = @@test.group(@keyf, {}, @initial, @reduce, true).sort {|a, b| a['count'] <=> b['count']}
+      results = @@test.group(@keyf, {}, @initial, @reduce).sort {|a, b| a['count'] <=> b['count']}
       assert results[0]['even'] && results[0]['count'] == 2.0
       assert results[1]['odd'] && results[1]['count'] == 3.0
     end
-
-    should "raise an error if trying to use keyf as a group eval" do
-      assert_raise OperationFailure do
-        @@test.group(@keyf, {}, @initial, @reduce)
-      end
-    end
   end
 
   context "A collection with two records" do