We report two cases of central retinal vein occlusion occurring after heart-lung transplantation in young adults. The patients underwent cardiopulmonary bypass during heart-lung transplantation, which may produce systemic hypotension and increased intraocular pressure. In addition, cardiopulmonary bypass is associated with disturbances in hemostasis and alterations in platelet function. Clotting factors frequently are administered during and after transplantation. Systemic hypothermia also is induced during cardiopulmonary bypass. Postoperatively, these patients developed hypertension and hyperlipidemia secondary to the immunosuppressive therapy used to help prevent rejection. It was postulated that these conditions may predispose a patient to having a central retinal vein occlusion.