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).