The stability of the catechol-specific fl-adrenergic receptor of turkey erythrocytes was tested with certain physical and chemical agents. The receptor for the catechol function was stable at high temperatures or to treatment with ultrasound. Phospholipase, Pronase, trypsin, Triton X-100, sodium lauryl sulfate, or Lubrol-PX destroyed the catecholamine-sensitive adenylate cyclase but not catecholamine-specific binding. Exposure to trypsin or Lubrol-PX released the catechol-specific receptor from the membrane. The solubilized material did not sediment at 100,000 x g and showed properties virtually identical with the receptor on the cell membrane. Association and dissociation rates, stability to physical and chemical agents, and K, for catecholamine binding were all similar for the particulate and the solubilized receptor. It was concluded that the binding material released by trypsin or Lubrol-PX represents the solubilized catechol-specific fraction of the P-adrenergic receptor site.