Laryngeal epithelium of monkeys (M. mulatta, M. nemestrina) ranging in age from late fetal to adult was found to undergo the following developmental changes: (1) progressive elaboration of commissural epithelium prenatally, reaching the adult form of pseudo-stratified columnar ciliated epithelium early in the postnatal period; (2) vocal process epithelium changing from cuboid to stratified squamous tissue during the late prenatal period, and (3) progressive increments in overall epithelial thickness during development, reaching a maximum in the early postnatal period. Chondrocyte density of the cricoid and thyroid cartilage decreased during the late prenatal period, reaching the adult form at the neonatal stage. The evidence suggests that mechanical or metaplastic stresses do not determine the observed tissue changes.