无精症（Azoospermia）通常指的就是无精子症；严格含义无精症含概无精子症和无精液症。

无精子症是男子不育症常见原因之一。在精液常规检查时找不到精子，必须离心后再检验， 经三次取样化验，如仍然找不到；方可确认报告无精子症。

无精液症常指不射精和逆行性射精所造成类似结果：男性性行动不以射出精液为终结。

但是，不射精和逆行性射精原因、结果在本质上全然不同：

Azoospermia is the medical condition of a man not having any measurable level of sperm in his semen. It is associated with very low levels of fertility or even sterility, but many forms are amenable to medical treatment. In humans, azoospermia affects about 1% of the male population and may be seen in up to 20% of male infertility situations.