Catecholamines play a central role in the regulation of energy expenditure, in part stimulating lipid mobilization through lipolysis in fat cells. The beta(2)-adrenergic receptor (ADRB2) is a major lipolytic receptor in human fat cells, and a recent study has shown that common polymorphisms occurring in codons 16 and 27 of the ADRB2 gene are significantly associated with obesity and lipolytic ADRB2 function in adipose tissue. We investigated whether previously described human ADRB2 gene polymorphisms are associated with obesity and diabetes in Korean subjects. According to the World Health Organization (WHO) criteria for oral glucose tolerance testing, 57 subjects had normal glucose tolerance (NGT), 32 had impaired glucose tolerance (IGT), and 106 had diabetes mellitus. The nondiabetic group (including NGT and IGT) consisted of 46 obese (defined as those with body mass index [BMI] of >or= 27 kg/m(2)) and 43 nonobese subjects (BMI < 27 kg/m(2)). The subjects with diabetes consisted of 62 obese and 44 nonobese subjects. There was no significant difference between nonobese and obese subjects in the allele frequency of ADRB2 gene polymorphisms at codons 16 and 27. There were no significant differences in BMI, percentage body fat, waist-to-hip ratio (WHR), systolic blood pressure, diastolic blood pressure and concentrations of fasting plasma glucose, fasting serum insulin, serum low-density lipoprotein (LDL)-cholesterol, serum high-density lipoprotein (HDL)-cholesterol, serum triglyceride, and serum free fatty acids, according to ADRB2 gene polymorphisms at codons 16 and 27. The frequency of the Glu27 homozygote was 1.1%. These findings suggest that genetic variability in the ADRB2 gene may not be a major determinant for the development of obesity and diabetes in Koreans.