In 1997-1999, 120 incident and histologically verified cases of stomach cancer were frequency matched on age, gender, residence, and urban/rural status with 360 controls to study the role of diet in gastric cancer in Uruguay. We focused on the role of plant sterols (beta-sitosterol, campesterol, stigmasterol, and total plant sterols) after controlling for major confounders. Total phytosterols were associated with a strong inverse relationship with stomach cancer (odds ratio of stomach cancer for total phytosterol intake in the highest tertile = 0.33, 95% confidence interval = 0.17-0.65). Joint exposure to high intake of total phytosterol and alpha-carotene was also inversely associated with gastric cancer risk (odds ratio = 0.09, 95% confidence interval = 0.02-0.32). High intake of total plant sterols explained most of the attenuation in risk of gastric cancer associated with vegetable and fruit intakes.