The sensitivity and selectivity of a propranolol-selective membrane electrode have been improved with the use of propranolol-ammonium reineckate as electroactive material in the presence of di-butyl sebacate as plasticizer and tetrahydrofuran as solvent mediator. The electrode exhibited a near-Nernstain response over a concentration range of 1x10-2-5x10-6M propranolol hydrochloride with a slope of 52.7±0.6 mV per decade. The practical pH range was 3-8. Interferences from common cations, alkaloids and drug excipients were reported. The proposed electrode has been successfully applied to determine propranolol hydrochloride in pure form and pharmaceutical preparations. The results were correlated well with those obtained by BP standard procedure.