Preliminary experience is reported in using mitomycin to improve the prognosis in trabeculectomy operations considered otherwise likely not to succeed. The medication is applied intraoperatively during an otherwise standard trabeculectomy procedure. Surgery was considered successful if the pressure was lowered to a predetermined target level, the only vision reduction was believed to be on the basis of cataract development, and there was no progression of cupping or visual field loss. With a follow-up of 6 to 42 months, the overall success rate is 84%.