A hospital-based case-control study of renal cell cancer was conducted in northern Italy between 1986 and 1989, with 240 cases of renal cell cancer (150 males and 90 females), and 665 controls (445 males and 220 females) chosen on the basis of age, sex, and area of residence. No associations were found between renal cell cancer and: body mass index (BMI); number of cigarettes smoked; age at starting to smoke; years of smoking; consumption of wine, beer, spirits, coffee, decaffeinated coffee; tea; intake of animal protein, fruits, and vegetables; various reproductive factors; hormonal use; sexual habits; sexually transmitted diseases; or selected occupational exposures. The odds ratio (OR) was above unity in smokers (OR = 1.34 for greater than or equal to 15 cigarettes/day), but the trends in risk with dose or duration were not statistically significant. Significant positive associations were found between renal cell cancer and sources of fat intake, especially margarine (OR for highest vs lowest intake = 1.71), and oils (OR = 1.89) whereas carrot intake showed a negative association (OR = 0.62). Also, a history of nephrolithiasis and multiple episodes of cystitis showed weak positive associations (OR = 2.00, 95 percent confidence interval (CI) 1.07-3.73; and OR = 1.60, 95 percent CI 0.95-2.70, respectively).