The aim of the study was to define minimal conditions necessary to isolate human spermatozoa using their swim-up potential. The efficiency of the isolation of spermatozoa from seminal fluid was tested after 1 hour incubation at 37 degrees C of seminal plasma together with isolation mediums, at the volume proportion 2:1. Three different media were tested: RPMI 1640, earle solution, and 0.9% solution NaCl. In the other experiments seminal fluid or RPMI 1640 were enriched with porcine follicular fluid and were incubated together. Sperm density and percentage of progressively motile sperms as well as their viability did not differ depending on the medium used. However, migration was weaker at higher sperm density. Addition of porcine follicular fluid to both seminal fluid and isolation medium lowered the efficiency of sperm migration to the isolation medium.