Busulfan is a carcinostatic which is used for myelocytic leukemia. A 42-year-old Japanese woman given high doses of busulfan for a short time was referred to us because of decreased visual acuity and blurred vision in both eyes. She received 212 mg/day of busulfan for only 4 days. Ophthalmoscopic examination demonstrated a posterior polar subcapsular opacity of the lens in both eyes. Although the occurrence of cataract due to busulfan has been reported after long-term administration of busulfan, this is the first clinical case of cataract caused by high doses of busulfan for a short period. It is necessary to pay more attention to busulfan cataract.