Previous studies have suggested that beta 3-adrenergic receptor (ADRB3) gene is associated with body mass index (BMI), which is an important predictor of bone mineral density (BMD). However, little is known concerning the effect of the ADRB3 gene on BMD. The present study investigated the relationship between ADRB3 Trp64Arg polymorphism, BMI and BMD in Turkish postmenopausal women. 133 postmenopausal women (81 osteoporotic and 52 healthy control) were recruited. For the detection of ADRB3 Trp64Arg polymorphism, polymerase chain reaction-restriction fragment lenght polymorphism (PCR-RFLP) techniques have been used. BMD was measured at the lumbar spine and hip by dual-energy X-ray absorptiometry. Distribution of ADRB3 Trp64Arg genotypes was similar in the study groups (p> 0.05). "Arg/Arg" genotype was not observed. In the osteoporotic group, subjects with "Trp/Trp" genotype tended to have lower BMI values compared to those with "Trp/Arg" genotype, the difference was closely tied to statistical significance (p= 0.052). Subjects with "Trp/Trp" genotype had also lower BMD values of femoral neck (p= 0.044) and total hip (p= 0.043) than those with "Trp/Arg" genotype. No significant effects of the ADRB3 Trp64Arg genotypes on BMI and BMD values were found in the control group. Our results suggested that ADRB3 Trp64Arg " Trp/Trp" genotype might be associated with osteoporosis risk by affecting body mass index and bone mineral density values in Turkish postmenopausal women.