Eighty-five eyes of 75 patients were retrospectively followed up for 5 years after argon laser trabeculoplasty. The effects of some treatment and patients variables on the results of trabeculoplasty were assessed. The laser power level or visible burn effect on the chamber angle did not have any statistically significant impact on the success rate or degree of intra-ocular pressure (IOP) decrease. A statistically significant level was reached by the degree of chamber angle pigmentation and the number of pre-operative antiglaucomatous medication. In eyes where trabeculoplasty was given as primary therapy, the IOP decrease was greatest.