Objectives: To compare temporal changes in BMI, overweight (BMI b 25 kg/m 2 ) and obesity (BMI b 30 kg/ m 2 ) between two periods, among adult Kuwaitis. Design: Comparison of two independent cross-sectional samples of Kuwaitis studied in 1980±81 and 1993±94. Subjects: 2067 (896 men and 1171 women) and 3435 (1730 men and 1705 women) adult Kuwaitis (aged ! 18 y), drawn from primary health care (PHC) clinics and studied for nutritional assessment and for prevalence of obesity in 1980±81 and 1993±94, respectively. Measurements: Weight was measured in kilograms and height in meters to obtain the body mass index (BMI), which is the weight in kilograms divided by the height in meters squared (kg/m 2 ). BMI b 25 and b 30 kg/m 2 were classi®ed as overweight and obesity, respectively. Results: Mean BMI (kg/m 2 ) increased signi®cantly (P`0.001) by 10.0 and 6.2% (2.5 and 1.7 kg/m 2 ) among men and women, respectively. Prevalence of overweight and obesity (BMI b 25 and b 30 kg/m 2 ) increased by 20.6 and 15.4% and by 13.7 and 8.4% among men and women, respectively. After controlling for sociodemographic differences between the two study periods, mean BMI was 2.0 and 1.6 kg/m 2 higher in 1993±94 than in 1980±81 among men and women, respectively. Prevalence of overweight and obesity (BMI b 25 and b 30 kg/m 2 ) also increased among both genders between the two periods (OR 2.1, 95% CI 1.7±2.7 and OR 1.9, 95% CI 1.5±2.4, for men and OR 2.2, 95% CI 1.6±3.0 and OR 1.4, 95% CI±1.0±1.9, for women). Conclusions: BMI, prevalence of overweight and obesity increased among Kuwaitis between 1980±81 and 1993±94, probably due to the effects of modernization, af¯uence, increased food consumption and the concomitant changes to sedentary lifestyles. The rate of temporal changes in BMI and obesity were higher, by comparison, in Kuwait than in selected other countries.