The influence of increasing amounts of zearalenone and de-oxynivalenol in diets for prepubertal pigs was investigated on 100 female piglets fed diets with increasing concentrations of ZON and DON (0.01mg ZON and 0.2mg DON/kg to 0.42mg ZON and 3.9mg DON/kg). Concentrations of 0.06mg ZON and 0.8mg DON per kg diet caused a significant decrease of serum concentrations of GLDH and FSH as well as vulva swelling. The uterus weight of the piglets receiving 0.42mg ZON and 3.9mg DON/kg was increased by almost 100% compared to the control. Furthermore, this group showed significantly decreased performance, serum protein concentration and zervix swelling. Further studies are needed to scrutinize the adverse effects of ZON and DON in diets for prepubertal female piglets, especially on future reproduction performance.