The objectives of this twelve-week feeding trial were to determine the effects of dietary Saccharomyces cerevisiae and/or zinc oxide on epididymal sperm characteristics, testicular morphometric traits, and growth parameters of bucks. 16 (New Zealand White) bucks 16-wk-old, weighing 2.8kg were randomly allotted to one of 4 treatment groups. Each treatment was replicated four times, with 1 buck per replicate, in a completely randomized design (CRD). Each treatment group was randomly assigned to one of the four commercial experimental diets designated thus: T A = control diet with no additives, T B = 0.12g/kg Saccharomyces cerevisiae, T C = 150mg/kg zinc oxide and T D = 0.12g/kg Saccharomyces cerevisiae +150 mg/kg zinc oxide. Although treatment had no effect (p>0.05) on final body weight, average daily weight gain and feed conversion ratio, epididymal sperm characteristics and testicular morphometric traits differed significantly (p<0.05). Bucks on T B (Saccharomyces cerevisiae-based diet) had improved (p<0.05) sperm concentration, motility and live sperm, tubule diameter, epididymal volume, volume fraction of duct, and total duct volume, but decreased testicular volume. Bucks fed T A (control diet) had improved volume fraction of tubule but recorded the highest incidence of head and tail sperm abnormality. Though, T C (zinc oxide-based diet) enhanced (p<0.05) seminal vesicle volume, sperm pH was better among bucks fed T D (Saccharomyces cerevisiae + zinc oxide-based diet). It can be concluded that dietary inclusion of Saccharomyces cerevisiae at 0.12g/ kg of feed improved epididymal sperm characteristics and testicular morphometric traits of rabbit bucks.