The role of various life style factors, including dietary habits, in the etiology of non-Hodgkin's lymphoma was investigated using data from a case-control study conducted in the northeastern part of Italy. This study was done on 208 histologically confirmed non-Hodgkin's lymphomas and 401 control subjects who were in the hospital for acute, nonimmunologic, or neoplastic conditions. Dietary histories concerned the frequency of consumption per week of alcohol, beverages that contain methylxanthine, and 14 select food items or groups of foods (including major sources of proteins, fat, fibers, and vitamin A in the Italian diet). The consumption of milk, liver, butter, oil (chiefly polyunsaturated oils), coffee, tea, and cola was positively related with non-Hodgkin's lymphoma risk. the consumption of whole-grain bread and pasta showed a protective effect. When a logistic model was fitted that included the aforementioned food items in addition to major nondietary covariates, all of the foods, except liver and beverages that contain methylxanthine, remained significant. Interestingly, these associations are in agreement with the positive correlation that is emerging internationally between the consumption of fat and proteins and non-Hodgkin's lymphoma.