Commonly male patients come for endocrine consultation of problems like lack of sexual development, erectile dysfunction, infertility, and gynecomastia. The necessary cause of primary hypogonadism is in testes that lead to low testosterone levels and thus increase in LH and FSH levels due to a negative feedback mechanism. The cause of hypogonadism is classified into two types such as primary hypogonadism and secondary gonadism. The history includes information about milestones of sexual development. Male reproductive examination mainly includes anthropometry, sexual maturity rating, looking for gynecomastia, and other common examination including fundus examination. The absence of physical findings in an adult does not rule out hypogonadism as deterioration of secondary sexual characteristics. The common cause for male infertility is idiopathic, followed by primary hypogonadism, genital tract obstruction, and secondary hypogonadism. The chapter also discusses clinical evaluation in gynecomastia, and erectile dysfunction. Hormonal tests such as LH, FSH levels, serum testosterone levels etc are performed to investigate male reproductive endocrine disorders.