ObjectiveTo describe clinical characteristics, hormonal profile and body composition of obese men in preoperative of bariatric surgery. MethodsCross-sectional, population-based study. Patients evaluated from June 2019 to December 2021 in 2 obesity referral centers. Patients underwent clinical evaluation, androgen deficiency screening using Androgen Deficiency in the Aging Male questionnaire, hormonal profile and body composition assessment through body mass index (BMI), body fat percentage (FM-%) and mass (FM-kg) measured by electrical bioimpedance and dual energy x-ray absorptiometry. To characterize hypogonadism, 2 cut-off points were considered: TT <264 ng/dL and TT <164 ng/dL. ResultsThirty patients were included, mean age 35.6 ± 8.8 years, mean weight 129.4 ± 14.0 kg and mean BMI 42.3 ± 4.7 kg/m2. Dyslipidemia was the most prevalent comorbidity. Considering TT <264 ng/dL, 22 patients (73%) had hypogonadism. The mean TT in hypogonadal men was 198.9 + 68.7 ng/dL and in eugonadal men 357.0 + 59.5 ng/dl (P < .001). Using TT <164 ng/dL, 7 patients (23%) had hypogonadism. The mean TT in hypogonadal patients was 116.6 + 28.9 ng/dL and in eugonadal patients 279.0 + 75.0 ng/dL (P < .001). In Androgen Deficiency in the Aging Male questionnaire, 93.3% had positive screening, with no significant difference between groups. There was no statistically significant difference in body composition between groups when using TT <264 ng/dL as the hypogonadism cutoff. Considering hypogonadism TT <164 ng/dL, hypogonadal patients had significantly higher values of weight (139.0 × 126.5 kg P = .036), BMI (46.1 × 41.2 kg/m2P = .014), FM-% (48.0 × 42.8% P = .010) and FM-kg (66.3 × 53.9 kg P = .007) than eugonadal patients. ConclusionHypogonadism was identified in at least 23% of patients. Considering TT below the lower limit of normality for characterization of hypogonadism, we identified a significant worsening in body composition parameters.