With the objective of examining the relationship between diet and adenocarcinoma of the lung, a case-control study was carried out in Uruguay. Red meat, total meat and fatty foods were associated with a significant increase in risk (odds ratios (OR) for red meat intake 1.92, 95% CI 1.27-2.90). On the other hand, fruits, tubers and all plant foods displayed significant inverse associations with adenocarcinoma of the lung (OR for total plant foods 0.39, 95% CI 0.26-0.61). Among nutrients, total fat, other fats (saturated fat) and cholesterol were associated with an increased risk of adenocarcinoma of the lung (OR for high consumption of total fat 2.28, 95% CI 1.48-3.54). The risk associated with cholesterol intake was even higher after controlling for total fat, suggesting that both nutrients (fat and cholesterol) have independent effects. Carotenoids and vitamin E displayed significantly protective effects. This effect was markedly attenuated, when these micronutrients were adjusted for total plant intake. Furthermore, red meat, fat, and cholesterol showed attenuation in its effects after adjustment for total plant foods. It could be concluded that tobacco smoking is the strongest risk factor for adenocarcinoma of the lung. Low consumption of plant foods, and in a lesser degree, high consumption of red meat, total fat and cholesterol contribute to a high risk of adenocarcinoma of the lung.