The roles of occupational exposure to aromatic amines, cigarette smoking, consumption of grilled or fried meats, and NAT2 genotype, along with dietary intake of ascorbic acid, were examined in 172 incident, histologically confirmed prostate cancer cases and 257 community controls in a case-control study conducted in Western New York during 1986-1991. Caucasian men, aged 45 to 85 and residing in Erie and Niagara county, were included. Controls were drawn from rolls of New York State motor vehicle license holders (younger than 65) and from the Health Care Finance Administration rolls (age 65 and over). These men completed an interviewer-administered questionnaire including usual consumption of foods, smoking history, occupational history, and medical history. They also agreed to have blood drawn for research purposes. Grade of differentiation of prostate tumor was collected by reviewing hospital case reports in the New York State Tumor Registry and pathology reports in the hospitals. Occupational aromatic amines were selected by using the 1981-1983 National Occupational Exposure Survey (NOES) job exposure matrix. Restriction fragment length polymorphism (RFLP) analysis was performed on DNA extracted from blood clots for NAT2 genotype.