Circulation will drop from ten million copies per issue to eight million from the beginning of next year.
Eva Dillon, the group publisher of Reader's Digest, said: "It makes sense for us because it's cost-efficient, and it makes sense for advertisers because it's more relevant to loyal readers."
Reader's Digest is the latest of a number of US titles to make so-called base-rate reductions to attract a more loyal readership and better-engaged audiences. They include Time, Women's Day, TV Guide and BusinessWeek.