Multiple primary malignant tumors of rhabdomyosarcoma in a upper arm and cancer of breast are extremely rare. In September 1970, a female, aged 86 years, underwent the first resection operation performed on a pleomorphic rhabdomyosarcoma of the right upper arm. She underwent radiation therapy (8000 rads at the operative field) postoperatively. In August 1980, a simple mastectomy was performed for a cancer of the right breast. In December 1984, fourteen years after her first operation, a recurrence was detected. The tumor recurred five times during the next two years and was resected each time. The patient died of cachexia sixteen years after the first operation.