Twenty-four male weaned piglets assigned to four diets containing 5.0, 10.0, 15.0 and 0.2 mg fumonisin B(1) (FB(1)) /kg as diets 1, 2, 3 and control diet, respectively, were used to study the effect of dietary FB(1) on growth and puberty attainment in pigs in a 6-month feeding trial. Lower feed intake during 0-4 months and a non-significant (p > 0.05) but FB(1) concentration-dependent decrease in live and DWGs in animals fed FB(1)-contaminated diets was observed at the end of the pubertal phase. The daily and the final live weight gains of animals fed diet 3 were 75.8% and 90.6%, respectively, of the control values. The mean ages at puberty by boars on diets 2 and 3 were significantly (p < 0.05) higher than those for animals on the control and diet 1. The animals on diet 3 attained puberty when mean live weight was 60.1 kg, some 30.3 days after the controls attained puberty, at 156.3 days, when the mean live weight was 46.9 kg. This study revealed that dietary FB(1) delays sexual maturity in growing pigs. Male weanling pigs for breeding should not be exposed to dietary FB(1) higher than 5 mg/kg for optimum growth and reproductive performance.