PURPOSE: Colorectal cancer (CRC) is the third most common cancer diagnosed in men and women in the United States. Given the availability of effective screening, most tumors are found early enough to offer patients substantial long-term survival. Thus there is a resulting significant population of CRC survivors for whom modifiable risk factors for recurrence and survival would be of interest. METHODS: We conducted a population-based retrospective cohort study among patients enrolled in 2 large Midwestern health plans for which claims data, including pharmacy fill data, and medical record data were available. Men and women who were 40 years of age or older at the time of CRC diagnosis with disease less than stage IV and no history of Crohn disease, ulcerative colitis, and irritable bowel syndrome were included. CRC cases diagnosed between January 1, 1990 and December 31, 2000 were included if they met the inclusion criteria. Adjusted Cox proportional hazard models were used with exposure modeled as a time-dependent covariate. We assessed progression-free survival, defined as an aggressive polyp or invasive disease, and overall survival. RESULTS: After adjustment for age at diagnosis, sex, race, body mass index, stage, side of initial tumor, and tumor histology, we found that current users of nonsteroidal anti-inflammatory drugs had a 3-fold decreased risk of recurrence and a >7-fold decreased risk of death. Our results are statistically significant with P-values <0.05. CONCLUSIONS: Our results suggest that current use of nonsteroidal anti-inflammatory drugs provides significant improvements in CRC outcomes.