The influence of fumonisin B(1) (a mycotoxin produced by Fusarium verticillioides) on sperm reserves and production of crossbred pubertal rabbits was studied using an experimental model that lasted 28 weeks. Forty-eight male rabbits, 7 weeks old and with average weight of 757.50+/-0.50 g, were allotted to four dietary fumonisin B(1) concentrations of 0.13, 5.0, 7.5 and 10.0 mg kg(-1) constituting diets 1 (control), 2, 3 and 4, respectively. The paired testes weight of rabbits fed diet 3 was significantly (P<0.05) higher than those fed diet 2 and the control. However, the epididymal weight was significantly (P<0.05) lower in rabbits fed the control diet as compared to others on test diets. The gonadal sperm reserves of the animals were significantly (P<0.05) reduced by the toxin with increased concentrations of the toxin in the diets. The sperm reserves per testis and per gram testis were significantly (P<0.05) higher in the control rabbits than those fed diets 3 and 4. The sperm reserves in caput, corpus and caudal epididymis declined significantly with each increase in the fumonisin concentration in the diets. The number of spermatozoa in total caput, corpus and cauda was significantly (P<0.05) higher in rabbits fed the control diet and the least in rabbits fed diet 4 containing 10.0mg fumonisin B(1)/kg. Extra-gonadal sperm reserves significantly decreased (P<0.05) in rabbits fed diets 3 and 4 compared to the control. The daily sperm production of the animals fed diets 2, 3 and 4 declined significantly to 67, 59 and 36% relative to those animals fed the control diet. This study suggests that exposure of breeding male rabbits to diets contaminated with fumonisin B(1) up to 7.5 mg fumonisin B(1)/kg will depress testicular and epididymal sperm reserves and sperm production and potentially impair reproduction in the animals.