American Express Cardmembers have been making online purchases on Amazon.com for years. Starting this month, they'll also be able to use their Membership Rewards points directly on the popular e-commerce website, without having to exchange their points for gift cards. Shoppers can use points for all or part of their purchases, making it even easier to redeem balances too small for some of the other perks offered directly through the rewards program.

To spend Membership Rewards points at Amazon.com, American Express Cardmembers just have to link their reward accounts to their online shopping profiles. First-time Amazon.com shoppers can create accounts for free. After linking accounts, shoppers can view the value of selected items in both cash and points.

American Express officials told reporters that the Amazon.com partnership is the latest membership perk to leverage the "pay with points" technology first introduced in 2005. While AmEx Cardmembers have successfully redeemed points for airline tickets and hotel stays directly with vendors, the Amazon.com deal marks one of the feature's highest profile launches.