OBJECTIVES. To estimate the soft tissue determined individual features of the upper airway sagittal size which may predispose the patient to snoring and OSA and to find whether there is any relationship between the patient's body-mass index (BMI) and the severity of OSA. MATERIAL AND METHODS. 58 consecutive patients with a mean age of 33.4 years were surgically treated for snoring and OSA. Before the operation they were subject to the following: physical examination, a sleep study to determine the severity of sleep disturbed breathing (SDB); the body mass index (BMI) was calculated, lateral cephalometry (LC) was recorded. RESULTS. Snoring was found in 25 patients, OSA I (mild) - 15, OSA II (moderate) - 9, OSA III (severe) - in 9 patients. Among patients with obesity, the most widespread types of sleep disorders were OSA II and OSA III. (p=0.029). There were differences in the mean values of the BMI between the group of snorers and the group with OSA II (p=0.007), between snorers and OSA III (p=0.006). Differences in upper airway cephalometric mean values between groups were found, the thickness of the uvula (SPT) between snorers and OSA III (p=0.001), between the OSA I and OSA III groups (p=0.032), and between the OSA II and OSA III groups (p=0.075). CONCLUSION. Our study found narrowing in the anterior-posterior dimension of the airway at all levels, correlating with the severity of OSA as well as the BMI. The narrowest place was found in the oropharynx with an extension to the hypopharynx.