Long-term results of trabeculotomy in juvenile primary open-angle glaucoma (JPOAG) were investigated based on a follow-up study of 16 eyes in 11 patients, diagnosed when they were between 10 and 45 years old. Preoperative visual field defects were found in 75% (12/16) of the eyes. After a mean follow up of 7 years (range, 1 to 18 years), 88% (14/16) of the eyes had an intraocular pressure (IOP) of 21 mm Hg or less (peak pressure at diurnal curves). Nine of these were receiving no medical treatment and five were being treated with beta-blockers and/or dipivefrin. The best results were in the younger patients; the success rate of those under age 40 years was 100%. After normalization of IOP, visual field testing showed no progression in defects. We conclude that trabeculotomy rather than filtering surgery should be used to treat JPOAG, because the success rate of filtering surgery decreases with decreasing age. Also, the good functional results achieved in these patients after normalization of IOP may indicate that ocular hypertension is the only risk factor in JPOAG.