The case of a 69-year-old woman with procainamide-induced agranulocytosis is reported, and literature reports of 14 other such cases are reviewed. The patients was exposed to procainamide, prescribed for atrial fibrillation, for 26 days, with a daily dose of 1.5 to 4 g and a total dose of 57.5 g. She recovered from agranulocytosis after discontinuation of the drug and hospital treatment for 16 days. Among the reported cases of procainamide-induced agranulocytosis, the daily dosage ranged from 750 mg to 4.5 g; the total ingested dose before agranulocytosis was observed ranged from 36.5 to 316.3 g. Patients treated with procainamide should be instructed to report any soreness of the mouth, throat or gums; unexplained fever; or any symptoms of upper respiratory tract infection. If white blood cell counts indicate bone marrow depression, the drug should be withdrawn and appropriate evaluation begun at once.