In 20 eyes (18 patients) with simple or capsular glaucoma in which a first full-circumference argon laser trabeculoplasty resulted in early or late failure, laser trabeculoplasty was repeated. In 12 eyes the second trabeculoplasty was clinically successful. At an average follow-up time of 30 months after second trabeculoplasty, the treatment was still successful in six patients. Early failure after the first treatment seems to be unfavourable for the outcome of secondary treatment. No correlation was found between the accumulated dose of laser energy delivered into the trabecular meshwork and the degree of intraocular pressure reduction after the second trabeculoplasty in this retrospective study.