Reversible and irreversible ototoxicity has been documented following the administration of various therapeutic agents. Reversible hearing loss is a known complication following the administration of quinine, salicylates and other nonsteroidal anti-inflammatory drugs, and erythromycin. We report a case of reversible hearing loss following OKT3 (murine monoclonal antibody CD3) administration. OKT3, a monoclonal antibody used as an immunosuppressant following cadaveric renal transplants, was associated with a transient sensorineural hearing loss that reversed following discontinuation of OKT3.