We evaluated the association between individual nonsteroidal antiinflammatory drugs (NSAIDs) and gastrointestinal (GI) toxicity in a retrospective cohort study aimed at examining and comparing the incidence of serious gastrointestinal disorders among NSAIDs users. We observed 2,302 GI hospitalizations among diclofenac, indomethacin, naproxen, piroxicam, sulindac, and other NSAIDs users in the province of Saskatchewan, Canada, from 1982 to 1986 for 228,392 persons who contributed 679,075 person-years of follow-up and filled close to 1.5 million NSAID prescriptions. Current NSAID users presented an increased risk of GI hospitalization [rate ratio (RR) = 3.9, 95% confidence interval = 3.5-4.4]. RRs decreased as time since the last prescription increased: 2.2 (1.9-2.6) for recent past users and 1.3 (1.1-1.5) for less recent past users. Among current users, RRs were the highest in indomethacin users (5.1, 4.3-6.0), and the lowest in sulindac users (3.1, 2.3-4.2). All of these results are adjusted for calendar time, sex, and age. Age showed a particularly strong association with the risk of GI hospitalization.