Men with azoospermia or severe oligospermia (< 5 x 10(6)/ml) should have genetic testing to identify the reason for male infertility before treatment. Identification of obstructive azoospermia (OA) or non-obstructive azoospermia (NOA) is essential because genetic testing differs for OA (which has normal testicular function, testicular volume, and FSH) versus NOA (which has small, soft testes and increased FSH). Among patients with NOA, history and physical examination along with laboratory testing is required to choose genetic testing specifically for primary testicular failure or congenital hypogonadotropic hypogonadism (HH). Genetic testing options include cystic fibrosis transmembrane conductance regulator (CFTR) testing for men with OA due to congenital absence of the vas, while karyotype, Y chromosome microdeletions (YCMD), and other specific genetic tests may be indicated if patient has severe oligospermia or NOA. These genetic tests help to identify which patients may benefit from medical and/or surgical intervention. The most recent techniques for genetic analysis will improve diagnosis and management of male infertility.