BACKGROUND To characterize sperm dynamic motility patterns and chromatin integrity in infertile men with leukocytospermia. METHODS Fifty patients with primary infertility and oligoasthenoteratozoospermia included in this prospective, controlled, blind study. All patients underwent clinical evaluation, semen peroxidase stain, computer aided semen analysis (CASA), sperm DNA integrity evaluation with acridine orange test (AOT) and fluorescence in situ hybridization (FISH) analysis of 18, X and Y chromosomes. Pregnancy outcomes were documented following antibiotic treatment of patients with leukocytospermia. RESULTS Infertile men with leukocytospermia had significantly lower progressive and total sperm motility percentages compared to the control group. Sperm dynamic motility parameters by CASA including curvilinear, straight line and average pathway velocities, straightness and amplitude of lateral head displacement were significantly lower in leukocytospermia. Sperm DNA fragmentation index was significantly higher in leukocytospermia. Percentages of sperm with disomy XY and 18 were significantly higher. These changes in sperm motility parameters and DNA integrity correlated with the number of peroxidase positive leukocytes. Follow-up of 23 of the 25 patients with leukocytospermia after antibiotic treatment revealed significantly higher pregnancy rates in cured patients than in those with persistent leukocytospermia. CONCLUSIONS Leukocytospermia has a significant impact on sperm dynamic motility patterns, DNA and chromosomal integrity in infertile men which can adversely affect the likelihood of a successful pregnancy.