The effect of prenatal administration of different doses of cortisone, corticosterone, dexamethasone, triamcinolone and prednisolone on the fetus and its palatal development was studied. All the glucocorticoids, except cortisone, produced cleft palate in the fetuses. Both the total frequency and morphologically different types of cleft palate were related to the dose of the teratogen. Triamcinolone appeared to be more potent than other glucocorticoid in inducing cleft palate. An association was noted between fetal growth inhibition, the dose of the teratogen and the frequency and type of cleft palate.