Examines whether traditional health practices and beliefs held by Vietnamese immigrants hinder access to health care and use of preventive health services. Study participants were Vietnamese immigrant adults living in San Francisco and Alameda Counties in California who were asked about traditional health practices, health insurance, and doctors’ visits. Results demonstrated that many of the Vietnamese had an understanding of disease quite different from that of the general U.S. population. Moreover, many of these Vietnamese retained certain traditional practices and beliefs, such as the use of Chinese herbs to ameliorate sickness and the notion that illness is caused by a humoral (ying and yang) imbalance, supernatural powers, or the wind. Nevertheless, these practices and beliefs did not explain either lack of health care access or underutilization of preventive health care. Instead, data showed that factors like having some form of health insurance and having a regular doctor were more likely to determine whether someone had received general check-ups or specific examinations. Efforts to improve preventive health care utilization among Vietnamese immigrants need to focus on lowering barriers to receiving health care, such as eligibility for health insurance coverage.