We present a case of an 85-year-old woman with medically refractory essential thrombocythemia and subsequent venous thrombosis. She received conservative phosphorus-32 sodium phosphate therapy for 3 mCi, approximately half the usual dose. One month later, she received a second intravenous phosphorus-32 treatment of 3.5 mCi. She responded successfully to both treatments with drops in her platelet count and experienced no adverse effects. Our case is noteworthy in the effectiveness from a conservative dose while avoiding hematologic complications.