PIP: The relationship between body weight and mortality is examined using U.S. data from the National Health and Nutrition Examination Survey I (NHANES I) Epidemiologic Follow-up Study concerning 13,242 individuals, the emphasis being on identifying the body mass index associated with the lowest levels of mortality. Factors such as smoking status, sex, race, and age are taken into consideration. The results suggest that only the interaction between race and body mass index is significant.