Objective: Chronic intermittent hypoxia due to respiratory events occurring during sleep and sleep fragmentation due to arousals in obstructive sleep apnea syndrome (OSAS) may affect bone mineral density (BMD) directly or may be by causing a change in BMD through effects on hormones. We aimed to investigate whether any BMD change or any change in the level of hormones [growth hormone (GH), insulinlike growth factor-1 (IGF-1), free testosterone, total testosterone, and sex hormone-binding globulin (SHBG)], which may be related to BMD, occurs in middle-aged male patients with OSAS and compare the same with normal individuals.Material and Methods: Blood samples were collected from the participants in the morning (07.00-08.00 AM) after applying polysomnography for diagnosis. GH, IGF-1, total testosterone, and SHBG levels were measured using the enzyme-linked immunosorbent assay method, whereas the free testosterone level was measured using the radioimmunoassay method. BMD was measured at the femoral neck and lumbar vertebra using the Dual energy X-ray absorptiometry (DEXA) method.Results: Between the two groups of hormones levels and T-score values statistically significant difference was not obtained. There was a statistically significant positive relationship between age and T-score femur (p<0.001) and T-score vertebra (p=0.017) and between rapid eye movement sleep time and T-score femur (p=0.032) in the OSAS group. Although patients who have BMD <-2.5 in the OSAS group (5/24) was detected to be higher than the control group (0/22), the difference was not statistically significant (p=0.05).Conclusion: In this study, we demonstrated that OSAS may not be a risk factor in the development of osteoporosis in middle-aged male patients. In addition, there was no direct relation between BMD and chronic intermittent hypoxia, apnea-hypopnea index, or excessive sleepiness. Furthermore, we could not obtain any distinct relationship between OSAS and hormonal parameters that affects BMD