Characteristics of neural corticosteroid receptors were studied in 51 adrenally-intact macaque monkeys using a modification of a corticosteroid receptor assay developed in this laboratory for rodent studies. Using cortisol as a ligand, two receptor subtypes could be distinguished and with similar Kd's to those observed in rodents, as measured with corticosterone. The time course showed maximum binding for mineralocorticoid receptors at 24 h and for glucocorticoid at 4 h. There were regional differences in the number of available binding sites for each receptor type, as well as an inverse correlation between the concentration of cortisol in the blood at the time of death and the number of available binding sites. In general this paper emphasizes the similarities between such receptors in primate and those in other species, similarities that could be detected despite the technical constraints of studying tissue taken from non-adrenalectomized animals.