To evaluate the safety and effectiveness of THC:YAG laser sclerostomy in reducing intraocular pressure (IOP), we performed 16 subconjunctival sclerostomies under a partial-thickness corneal flap. We report the 3- and 6-month follow-up results in these patients, all of whom had intractable glaucoma resistant to previous surgical treatment. The mean IOP decreased from a pretreatment value of 30 mm Hg to a posttreatment value of 14 mm Hg at 3 months. Fifty-seven percent of the treated eyes achieved an IOP below 20 mm Hg at 6 months. A significant reduction in glaucoma medications is also reported among the successes. Complications were minimal.