Data on potential risk factors for primary liver cancer (PLC), including hepatitis B virus (HBV) infection, contaminated drinking water, maize consumption, and use of tobacco and alcohol were collected from 12,222 males over 40 years of age living on Chongming Island, a high-risk area for PLC. During the first 3 years of follow-up (1980-82), 70 deaths from this disease occurred among study subjects. Preliminary results indicate that HBV carriers were 6.7 times more likely to die of PLC than were noncarriers (P less than .05). No association was found between PLC and alcohol consumption. More data are needed for evaluation of the relationships between cigarette smoking, maize consumption, contaminated drinking water, and PLC on Chongming Island.