We examined associations between long-term daily use of adult-strength aspirin (≥325 mg/day) and both overall cancer incidence and incidence of 10 types of cancer among 69810 men and 76303 women participating in the Cancer Prevention Study II Nutrition Cohort, a relatively elderly population. Aspirin use was reported at enrollment in 1992–1993 and updated in 1997, 1999, and 2001. Multivariable Cox proportional hazards regression was used to calculate rate ratios (RRs).