Cryopreservation of human fetal adrenomedullary cells was performed, after dissociation of the gland and purification of chromaffin aggregates, using 10% dymethyl sulfoxide as cryoprotectant. More than 90% of thawed cultured clusters appear morphologically intact, showing extensive neurite outgrowth and absence of appreciable cellular loss. Immunoreactivity for tyrosine hydroxylase and response to nerve growth factor were demonstrated. These findings indicate that human medullary cells maintain their distinctive functional characteristics after cryopreservation.