INTRODUCTIONThis protocol describes a method for inducing ovulation in Xenopus laevis for the purpose of in vitro fertilization. Ovulation is induced by injection of human chorionic gonadotropin (hCG) into the dorsal lymph sac of a female frog. Females can lay many hundreds of eggs. However, because the actual number of eggs laid and the efficiency of fertilization are unpredictable, ovulation should be induced in more than one female, even when only a few eggs are required.