['To determine the prevalence of and associated factors for overweight, especially to determine the relationship between the intake of monosodium glutamate (MSG) as a seasoning and overweight in Vietnam.', 'A cross-sectional survey was conducted of Vietnamese adults aged ≥20 years in 2008. Dietary intake was assessed by the 24 h recall method for 3 d. MSG intake was evaluated by the weighing method on three consecutive days. Physical activity was assessed based on the Global Physical Activity Questionnaire recommended by the WHO. Overweight was defined as BMI ≥ 23·0 kg/m2. Other characteristics such as age and lifelong occupation were determined by a structured questionnaire.', 'Some rural and urban areas of Hanoi, Thua Thien Hue Province and Ho Chi Minh City, Vietnam.', 'A total of 1528 adults living in surveyed areas were randomly selected by the multistage cluster sampling method.', 'The prevalence of overweight was 27·9 %, and 81·0 % of participants were MSG users. Average MSG intake was 2·2 (sd 1·8) g/d. Multiple logistic regression analysis revealed that factors associated with overweight were age, region of residence, lifelong occupation, physical activity and intakes of energy, carbohydrates, saturated fat and animal protein. There was no significant association between MSG intake and overweight.'] Is monosodium glutamate associated with overweight in Vietnamese adults?