Epithelial and stromal cells were isolated from endometrium of cyclic heifers by enzymic dispersion. These cells exhibited specific morphological and functional properties. Epithelial cells appeared cuboidal or columnal and showed contact inhibition as they reached confluence. Stromal cells were fibroblast-like and enlarged at the time of confluence after which they overgrew in multiple layers. The presence of specific receptors for PGE-2 and beta-adrenergic catecholamines (isoproterenol) was estimated by activation of adenylate cyclase. Stromal cells had more adenylate cyclase activity (P less than 0.01) than did epithelial cells before (basal) and after stimulation with guanosine triphosphate (GTP) and PGE-2. However, epithelial cells were much more responsive to isoproterenol (P less than 0.01). Treatment of cultured cells with indomethacin to block PG synthesis increased the sensitivity and maximal response to PGE-2 in stromal (P less than 0.01) but not in epithelial (P greater than 0.1) cells. The latter result suggested autologous desensitization of the PGE-2 response resulting from synthesis of PGs in cultured cells. Both cell types synthesized PGs in culture: PGF-2 alpha was synthesized in greater quantity in epithelial than in stromal cells (P less than 0.05) while stromal cells synthesized more PGE-2 than did epithelial cells (P less than 0.001). Endometrial cells separated in this way should prove useful for study of their specific role in the processes of implantation and maternal recognition of pregnancy.