BACKGROUND: The pressure lowering effect of Argon laser trabeculoplasty (ALT) has been well demonstrated in the past. Today some clinicians tend to avoid ALT perhaps because it has been used in erroneous indications. The aim of this study was to re-evaluate the usefulness of ALT and to define its indication in the treatment of glaucoma. PATIENTS AND METHODS: A collective of 81 patients treated by ALT entered in a data bank between 1989 and 1991 were analysed retrospectively, focussing on: the percentage of patients requiring trabeculectomy (TE) after ALT, the mean time from ALT to TE, the stage of disease progression at which the decision for ALT was taken and the post-ALT evolution of ocular pressure (IOP), visual field and optic disc. RESULTS: After a mean follow-up of 28 +/- 10.5 months a TE was performed in 25% of cases. It was found that in our clinical practice the decision for ALT tended to be taken at a rather late stage of disease. For the patients that did not need a TE, the mean decrease of IOP at the end of follow-up was 5.4 mm Hg and the analysis of glaucoma parameters showed that there was no significant worsening of disease. The disease progression in the group of patients that were operated was already significantly worse than the total collective before ATL was performed. CONCLUSIONS: ALT is useful in the treatment of glaucoma, as long as it is not considered as an alternative to TE and as long as the patients benefit from a strict follow-up. Advanced cases should however be operated without delay.