We used vitrectomy and transvitreal endophotocoagulation of the ciliary processes to treat 18 eyes with severe glaucoma that could not be managed successfully by medical therapy and conventional glaucoma surgery. Lensectomy was performed in the two phakic eyes in the series because of cataractous lens changes. A pars plana vitrectomy was done in each eye and a fiberoptic probe used to apply transvitreal blue-green argon laser photocoagulation directly to the ciliary processes. Treatment of more than 180 degrees was necessary for sufficient lowering of the intraocular pressure. Postoperative intraocular pressure was equal to or less than 20 mmHg in 14 of 18 eyes, although nine of the 14 successful cases required postoperative medical therapy. Complications included transient vitreous hemorrhage (2 eyes), transient choroidal detachment (2 eyes), and hypotony (1 eye).