The risk of gestational trophoblastic disease in relation to frequency of consumption of selected dietary items was evaluated with data from a case-control study conducted in Northern Italy on 148 women with histologically confirmed gestational trophoblastic disease and two control groups, one consisting of 372 obstetric control subjects and one consisting of 406 patients in the hospital for acute, nonobstetric, nongynecologic conditions. Patients with gestational trophoblastic disease tended to consume several foods less frequently, including the major sources of vitamin A and animal protein in the Italian diet. Relative risk estimates were significantly below unity in both control groups for green vegetable, carrot, liver, and cheese consumption and in the obstetric control group only for milk, meat, eggs, fresh fruit, and fish. Inverse relationships emerged between the risk of gestational trophoblastic disease and beta-carotene or retinol intake index. The trend of decreasing risk with increasing intake was significant for beta-carotene consumption. The present findings confirm that various aspects of diet may influence the risk of gestational trophoblastic disease. However, the limitation of available evidence still introduces serious uncertainties in the interpretation of these findings and suggests the potential importance of further epidemiologic and biochemical research to obtain more precise definition of specific dietary correlates of gestational trophoblastic disease.