Objective. Evaluation of the pathogenic factor of autoimmune hypogonadism in men with a positive MAR IgG test result and type 1 diabetes mellitus (DM1) in a South American cohort. Materials and Methods. The retrospective study included 97 men with a positive MAR IgG test result: 30 patients with T1DM and 67 men without diabetes. The examination included determination of total testosterone and titer of antibodies against steroid-producing cells of reproductive tissue. Differences were considered statistically significant when p<0.05. Results.The incidence of high titers of autoantibodies against steroid-producing cells (Leydig cells) of the testes (CPT) in patients with T1DM and a positive MAR test is statistically significantly higher than in people without diabetes. In both groups, testosterone levels were statistically significantly lower with an increased CPT titer than with a normal titer. The incidence of hypogonadism in men with a high CPT titer was statistically significantly higher than in patients with a normal titer. Conclusion. Autoimmune hypogonadism is a common complication in men with T1DM and a positive MAR IgG test result and is associated with the formation of antibodies against steroid-producing cells of the reproductive tissue.