Najafi L, et al. - In this study, effects of canthaxanthin on human sperm parameters during the freeze-thaw process were examined. Twenty-five normozoospermic semen samples were included and were divided into five groups including 0, 0.1, 1, 10, and 25 µM of canthaxanthin. Using a rapid freezing technique, the prepared spermatozoa were cryopreserved. Before freezing and after thawing, researchers evaluated sperm motility, viability (eosin-nigrosin), morphology (Papanicolaou), acrosome reaction (double staining), DNA denaturation (acridine orange), chromatin packaging (aniline blue and toluidine blue), and DNA fragmentation (sperm chromatin dispersion test). Significant decrease in all sperm parameters after thawing vs before freezing was noted. Significant improvement in the progressive and total motility, viability, normal morphology, chromatin packaging, acrosome integrity and DNA denaturation and fragmentation was noted with 25 micromolar canthaxanthin. Significant improvement in the progressive and total motility, viability, normal morphology, chromatin packaging, acrosome integrity and DNA denaturation and fragmentation was noted with 10 micromolar canthaxanthin. Whereas, significant differences only in the improvement of acrosome integrity, chromatin packaging (toluidine blue) and DNA denaturation and fragmentation were observed in 1 µM group. But, no significant differences in any of measured parameters were noted in 0.1 µM group. findings thereby suggest the ameliorating effect of canthaxanthin on detrimental influences of cryopreservation on human sperm parameters.