Objective: to evaluate the preavalence and characteristics of hypogonadism in obese man. Research and Methods: Thestudy was performed in 31 obese man (aged 33 [22;44], BMI 40 [34,4;44,0]. Measurements during the study: chemistry panel, testosteroa and LH levels, immunoreactive insulin, HOMA index calculation. Statistically significant difference w as considered as p < 0,05. Results. Hypogonadism preavalence was 80,6%. The hypogonadism prevalence and testosterone level was more depended on age and obesity but less on duration. 100 % risk of hypogonadism w as observed in heavily obese patients. There w as no increase of LH levels. In man with low testosterone lev els HOMA index w as significantly higher со mpared to healthy subjects. Conclusion: The prevalence of normogonadotropic hypogonadism in obese men is extremely high and it represents an evidence of functional disorder of hypophyseal gonadal system. Thedecrease of testosterone levels is age-coinciding, but it is more pronounced in obese nan.