In a retrospective study we compared the efficacy and safety of trabeculectomy and nonpenetrating trabeculectomy (NPT). In the latter procedure under a thin scleral flap, juxtacanalicular trabecular meshwork with Schlemm's canal is excised leaving the innermost trabecular meshwork behind. Trabeculectomy was performed on 86 eyes (66 blacks, 20 whites), whereas 71 eyes underwent NPT (44 blacks, 27 whites). The mean follow-up period was 1.7 years. Postoperatively at one year, trabeculectomy controlled 70.3% of patients with no or topical antiglaucoma medication, whereas 83.7% of NPT patients were similarly controlled. There was a difference in the number and severity of complications between trabeculectomy and NPT. Postoperative flat anterior chamber, uveitis, hyphema, vitreous loss, and choroidal detachment occurred more frequently after trabeculectomy.