ABSTRACT Thirty-nine eyes of 20 premature infants, mean birthweight 922 g, mean gestational age 27 weeks, with active retinopathy of prematurity (ROP), were treated. Thirty-one eyes with stage 3+ ROP and 180° to 360° of preretinal neovascularization received cryotherapy to ablate the zone of peripheral avascular retina. All underwent complete regression of active disease. Eight of these eyes subsequently developed retinal detachments due to ongoing vitreous traction. One detachment was inoperable. Six eyes were successfully reattached following scleral buckling surgery. One of these six redetached and became inoperable after 20 months. Pars plicata vitrectomy was not successful in reattaching the eighth case. Twentyeight of these 31 eyes retain useful visual acuity with follow-up of 15 to 70 months (mean 41 months). There have been no complications resulting from cryotherapy. Eight other eyes with stage 4 ROP (traction retinal detachment) were treated with cryotherapy and scleral buckling surgery. All were initially reattached, but ongoing vitreoretinal traction caused redetachment in five. One was inoperable. "Open sky" vitrectomy was successful in reattaching three of the other four. Of the six cases that remained reattached with follow-up of 6 to 51 months, only two retain useful vision.