Hereditary protein C deficiency results in a hypercoagulable state that can manifest itself as venous thrombosis and pulmonary embolism. The prevalence of this condition, even among patients with familial thrombosis, is quite low. We report a case of protein C deficiency presenting as massive pulmonary thromboembolism in a patient with hereditary spherocytosis, an uncommon hemolytic disorder not usually associated with increased thrombotic risk. A review of the literature revealed only a few cases of thrombosis associated with hereditary spherocytosis, and none of them had protein C deficiency. This makes the present case the first of its kind to be reported.