The epididymis receives sperm from the seminiferous tubules of the testis and stores it.

It takes about 20 days for sperm to pass through the 6-m-long tubules of each epididymis of a human male. During this passage, the sperm become motile and gain the ability to fertilize.

During ejaculation, the sperm are propelled from the epididymis through the muscular vas deferens.