This study compares long-term efficacy (up to 48 months) of cyclocryocoagulation and trabeculectomy in lowering the intraocular pressure (IOP). Intraocular pressure evolution after cyclocryocoagulation in one eye and trabeculectomy in the fellow eye for the treatment of primary open- and narrow-angle glaucoma was monitored in five patients. After 4 years both interventions were still active. Cyclocryocoagulation was slightly less effective in lowering IOP but associated with considerably less complications than trabeculectomy.