Membrane-enriched homogenates of fresh and cultured (48 h) porcine lymphocytes were assayed for the presence of specific LHRH receptors by saturation and displacement analysis using [D-Ser-(TBU)6, des-Gly-NH2(10)] LHRH-EA as the labeled and unlabeled ligand. Membrane-enriched homogenates of porcine pituitaries served as positive controls while porcine granulosa cell membranes and crude liver homogenates served as negative controls. Specific high-affinity LHRH receptors were found in porcine pituitaries (Kd = 0.3 nM) and cultured lymphocytes (Kd = 13 nM) but not in fresh lymphocytes. No specific binding was observed in negative control tissues. Porcine lymphocytes have measurable high-affinity LHRH receptors after 48 h of culture.