Five patients with severe interstitial cystitis that had not responded to conventional means of therapy were treated with the neodymium-YAG laser. Of the 5 patients 4 demonstrated cessation of severe bladder pain and frequency of urination within several days after therapy. These patients also were studied objectively by measuring bladder capacity, which was found to be increased over-all. Complication rates from this modality of therapy were extremely low. The patients have been followed for 3 to 15 months after treatment and to date have had no recurrent symptoms of severe interstitial cystitis, although some have had mild recurrent voiding symptoms.