The dissociation of the processes of ovulation and maturation of full grown Rana pipiens ovarian oocytes has been demonstrated by the in vitro exposure of ovarian fragments to amphibian pituitaries or to the mammalian steroids, progesterone, and deoxycorticosterone acetate. With optimal concentrations of these substances, and under controlled conditions, all of the full grown oocytes can be stimulated to undergo germinal vesicle brcakdown and maturation to the second meiotic metaphase while still in the ovarian fragment. Such oocytes are physiologically mature as shown by their positive response to a n activation stimulus. That ovulation and maturation are not interdependent processes is further demonstrated by the liberation from the ovary of occasional oocytes which do not possess any follicular investments, but do possess an intact germinal vesicle. Such oocytes do not respond to a n activation stimulus. The responses of ovaries to the action of pituitary extracts and steroid suspensions indicate that steroids are more efficient inducers of oocyte maturation while pituitary factors are better inducers of ovulation. These data, discussed with other findings, suggest the possible roles played by pituitary gonadotropins and steroid hormones in ovulation and physiological maturation of the anuran egg.