Northwest Airlines recently announced that it has added Avis Rent A Car to WorldPerks, allowing members to earn additional miles while saving up to 25 percent off Avis rentals in the United States and Canada.

WorldPerks members can now earn 50 WorldPerks miles per day for Avis rentals of one to four days, and 500 WorldPerks miles for Avis rentals of five days or more. To earn miles, members must provide their WorldPerks number at the time of rental.

To celebrate this new alliance, Northwest and Avis are offering WorldPerks members 1,500 bonus miles on rentals of two days or more, through May 31, 2008. To receive the bonus miles, members must mention coupon number MUAA122 at the time of reservation. For more information, including terms and conditions, visit avis.com/nwa1500.

More than 70 different businesses offer WorldPerks members the opportunity to earn WorldPerks miles, just by doing business with companies they do business with every day. Mileage partners encompass car, hotel, financial services, dining and retail and will soon include grocery, energy and dry cleaning businesses. For a complete list of WorldPerks partner business, or to enroll as a WorldPerks member, log on to nwa.com/worldperks.