Aim: To determine the effect of oral administration of an aqueous extract from the roots of Lepidium meyenii (maca) on spermatogenesis in adult male rats. Methods.. Male rats received an aqueous extract of the root (66. 7 mg in one mL) twice a day for 14 consecutive days. Results, Treatment with Lepidium meyenii resulted in an increase in the weights of testis and epididymis but not the seminal vesicle weight. The length and frequency of stages IX-XIV seminiferous tubules, where mitosis occurred, were increased and stages I-VI were reduced in rats treated with Lepidium meyenii. Conclusion: The Lepidium meyenii root invigorates spermatogenesis in male rats by acting on its initial stages (IX-XIV).