Background Many low- to middle-income countries are faced with an increasing prevalence of overweight/obesity while that for underweight remains high, a duality termed “double burden”; both are key risk factors for chronic diseases. This cross-sectional study assesses the prevalence and factors for underweight and overweight/obesity among adults in Danang, Vietnam, using WHO standard and suggested Asian-specific BMI cut-offs. Methods In 2010, 1713 residents age ≥35 years from 900 households in 6 of 56 urban, rural and mixed urban–rural communes in Danang were selected using multistage-cluster sampling methodology to participate; 1621 qualified adults enrolled. Participants completed a health survey based on WHO STEPwise Approach to Chronic Disease Risk Factor Surveillance and additional questions on chest pain and stroke symptoms. Anthropometric and other measurements were conducted. Relative risk regression was used to identify independent risk factors for underweight or overweight/obesity according to WHO standard cut-offs and suggested Asian-specific cut-offs (