Although Vietnamese refugees are the fastest-growing Asian minority in the United States, little is known about their health knowledge and practices, especially regarding cancer prevention. To address this problem, we interviewed a randomly selected sample of 215 Vietnamese adults living in the San Francisco Bay Area. Results indicated that 13% had never heard of cancer, 27% did not know that cigarette smoking can cause cancer, and 28% believed that cancer is contagious. Although hepatitis B-related liver cancer is endemic among Vietnamese, 48% had never heard of hepatitis B. Among men (n = 116), 56% were smokers (versus 32% in the general US population). Male cigarette smoking was significantly associated with incomes below the poverty level (P less than .01), residence in the US for 9 years or less (P less than .05), not knowing that smoking causes cancer (P less than .05), and limited English proficiency (P less than .01). Binge drinking was reported by 35% of men. Young Vietnamese of both sexes reported consuming diets higher in fat and lower in fiber than when they lived in Vietnam. Among eligible women, 32% had never had a Papanicolaou test (versus 9% of US women), 28% had never had a breast examination (versus 16%), and 83% had never had a mammogram (versus 62%). Education about cancer and its risk factors, smoking cessation, and cancer screening are high priorities for this population.