Azoospermia is the complete absence of sperm cell in the ejaculate.

Obstructive azoospermia (48% of cases) is caused by a blockage of both posttesticular genital tracts.

Non obstructive azoospermia is indicative of a lack of production of sperm cell by the testes and can be caused by chromosomal abnormalities, infections, endocrine or metabolic disorders or environmental causes.