Rats were intragastrically infused with hydrolyzed starch (16% Polycose) or water as they drank cherry- or grape-flavored water during 23-h/day tests; chow was available ad libitum. After 4 conditioning days the rats displayed a near-total preference (96%) for the starch-paired flavor over the water-paired flavor in two-choice tests. This conditioned flavor preference persisted during a 4-day extinction test when both flavors were paired with water infusions. The results demonstrate that the postingestive actions of starch are rewarding to nondeprived rats and can condition strong and long-lasting flavor preferences.