Acute radiation cystitis occurs during or soon after radiation treatment. It is usually self-limiting, and is generally managed conservatively. Late radiation cystitis, on the other hand, can develop from 6 months to 20 years after radiation therapy. The main presenting symptom is hematuria, which may vary from mild to severe, life-threatening hemorrhage. Initial management includes intravenous fluid replacement, blood transfusion if indicated and transurethral catheterization with bladder washout and irrigation. Oral or parenteral agents that can be used to control hematuria include conjugated estrogens, pentosan polysulfate or WF10. Cystoscopy with laser fulguration or electrocoagulation of bleeding points is sometimes effective. Injection of botulinum toxin A in the bladder wall may relieve irritative bladder symptoms. Intravesical instillation of aluminum, placental extract, prostaglandins or formalin can also be effective. More-aggressive treatment options include selective embolization or ligation of the internal iliac arteries. Surgical options include urinary diversion by percutaneous nephrostomy or intestinal conduit, with or without cystectomy. Hyperbaric oxygen therapy (HBOT) involves the administration of 100% oxygen at higher than atmospheric pressure. The reported success rate of HBOT for radiation cystitis varies from 60% to 92%. An important multicenter, double-blind, randomized, sham-controlled trial to evaluate the effectiveness of HBOT for refractory radiation cystitis is currently being conducted.