Enucleated Xenopus laevis oocytes were activated by incubation in progesterone for a period sufficient to induce maturation in control oocytes. Cytoplasm from such hormone-activated enucleated oocytes induces maturation when injected into untreated oocytes. Injection of activated cytoplasm induces maturation faster than injection of progesterone. In addition, serial transfer and time course experiments suggest that progesteron is not the effective transferred agent. These results suggest that progesteron-induced maturation is initially a cytoplasmic event not requiring the participation of the germinal vesicle. Since it has been previously shown that puromycin and cycloheximide inhibit maturation, these results imply a two-step mechanism most probably at the translational level.