Objective — to investigate the influence of Trichomonas vaginalis-derived secretory products on functional status of human sperm. Material and methods. The allocation of Trichomonas vaginalis was performed from clinical material (ejaculate) obtained from patients with chronic trichomoniasis and normospermia (n=3) or pathospermia (n=9). 12 samples of Trichomonas vaginalis were investigated. The standard semen analysis and hypoosmotic swelling test (HOS-test) were used to assess the toxicity. Results. Products secretion of Trichomonas vaginalis flagellar forms after 2 hours of incubation caused the decrease in sperm motility category «a» and «a+b» in comparison with the control group (p<0.01). HOS-test showed significant (p<0.01) worse results after the action of secretory products of Trichomonas vaginalis compared to control group. Conclusion. Products of flagellar forms of Trichomonas vaginalis have substantially more pronounced toxic effect on human spermatozoa compared with secretory products of round forms of Trichomonas vaginalis (p<0.01). HOS-test showed high sensitivity and it is recommended for early detection of human sperm injury by secretory products of flagellar and round forms of Trichomonas vaginalis.