Aim: docosahexaenoic acid is one of the most common fatty acids in the cell membranes of sperm. This substance is a structural component of cell membranes, and is responsible for such properties as plasticity and fluidity which are necessary for the implementation of the process of capacitation and acrosome reaction. In addition, docosahexaenoic acid has antioxidant properties. Aim of our study was to assess the effect of dietary supplement docosahexaenoic acid (Brudi PLUS) on such markers of male fertility as the sperm DNA integrity, standard indicators of semen analysis and cryotolerance in infertile men. Materials and methods: a randomized, multicenter, double-blind, placebo-controlled study was conducted. A total of 109 infertile men were recruited to participate in the study. All patients underwent different analyzes, including semen analysis, sperm DNA fragmentation, MARtest, test of cryotolerance and electron microscopy analysis of spermatozoa. In active treatment group patients were prescribed to drug containing 350 mg of docosahexaenoic acid 3 times a day for 90 days. In the control group, patients were administered to a placebo with a similar scheme. All analyzes were repeatedly performed after 3-months of therapy. Results: An increase in the progressive mobility and sperm viability was determined after the test of cryotolerance in the active treatment group. According to electron microscopy analysis of spermatozoa, positive changes were observed in the number of heads of the normal form with the normal structure of chromatin and acrosome, as well as a decrease in the number of spermatozoa with insufficiently condensed chromatin. Conclusions: the therapy with drug Brudi PLUS in patients with male infertility allows to increase in cryotolerance of sperms as well as decrease in number of sperm ultrastructure defects. © 2019, IBionika Media Ltd. All rights reserved.