Aims: To compare selective laser trabeculoplasty (SLT) and argon laser trabeculoplasty (ALT), in terms of intraocular pressure (IOP) lowering, in patients with open-angle glaucoma. Methods: 176 eyes of 152 patients were enrolled in this study, 89 in the SLT and 87 in the ALT groups. Patients were randomised to receive either SLT or ALT treatment to 180° of the trabecular meshwork. Patients were followed up to 12 months after treatment. The main outcome measured was IOP lowering at 12 months after treatment, compared between the SLT and ALT groups. Results: No significant difference (p = 0.846) was found in mean decrease in IOP between the SLT (5.86 mm Hg) and ALT (6.04 mm Hg) groups at 1 year or at any other time points, nor were there any significant differences in the rate of early or late complications between the two groups. Conclusions: SLT is equivalent to ALT in terms of IOP lowering at 1 year, and is a safe and effective procedure for patients with open-angle glaucoma.