The aim of this study was to evaluate the efficacy of the PureSperm density gradient centrifugation on the selecting sperm with less chromosomal aneuploidy. Semen samples were obtained from 30 infertile men with teratozoospermia and 15 fertile men with normal semen parameters. The frequencies of numerical chromosomes aberrations were simultaneously identified in neat semen and in the different fractions of the density gradient centrifugation from the same samples. Using a triple colour FISH, we show that patients with severe teratozoospermia have a significantly increased frequency of chromosomal abnormalities in their neat semen compared with normozoospermic men (P < 0.001). The mean sperm motility and sperm morphology were improved significantly after semen processing with three layers PureSperm gradient compared with whole semen (P < 0.001). In addition, aneuploidy frequencies were lower in specimens enriched by the gradient centrifugation compared with unprocessed semen. Significant differences were observed in the disomy rates for the autosome and for either sex chromosome between the neat semen and the different PureSperm fractions (P < 0.001). In conclusion, our study shows that semen processing by density gradient centrifugation is very efficient in reducing sperm with aneuploidy and diploidy.