This study investigated the factors associated with success in meeting the dietary goals of the Polyp Prevention Trial (PPT), a 4-y low-fat, high-fiber, high-fruit/vegetable dietary intervention. The PPT provided a rare opportunity to assess factors in long-term adherence to a dietary pattern that required changes to multiple aspects rather than a single aspect of diet. Demographics, health indicators, and dietary intake were assessed at baseline and annually for 4 y of follow-up. Participants (n = 833) received dietary and behavioral counseling to support adherence to trial dietary goals. We assessed the association of baseline variables and trial participation with success in meeting dietary goals. Participant adherence to the intervention goals was significantly associated with never smoking, no history of weight gain, and consumption of less fat and more fiber, fruits, and vegetables at trial baseline. Successful participants were also more educated and married, whereas those with the poorest adherence were older. In addition, successful participants demonstrated greater participation throughout the trial, including attendance at counseling sessions, completion of dietary records, and contacts with staff. Of particular interest were the behavioral and demographic characteristics that distinguished the subset of participants who achieved most or all dietary intervention goals across all 4 study years who we termed Super Compliers. These individuals also were more likely to adhere to social norms for healthy lifestyles and demonstrated greater adherence to other aspects of trial participation. J. Nutr. 137: 391-398, 2007.