We used the diode-laser indirect ophthalmoscope in the treatment of 17 (30 eyes) infants with zone 1 (a circle centered on the optic disk with a radius of twice the distance from the disk to the fovea) threshold retinopathy of prematurity (at least five continuous or eight cumulative 30-degree sectors [clock hours] of ridge with extraretinal fibrovascular proliferation in the presence of plus disease). Mean follow-up was 31.2 weeks. Two eyes (6.7%) required retreatment of missed areas that had persistent plus disease (enlarged posterior veins and tortuous arterioles). A favorable outcome was attained in 25 eyes (83.3%). Five eyes (16.7%) developed retinal detachments, three of which remained stable at Stage 4A (extrafoveal retinal detachment) and two of which ultimately progressed to Stage 5 (total retinal detachment). Both eyes that went on to Stage 5 had severe posterior pole hemorrhages at the time of treatment. Two eyes that developed retinal detachments (one, stage 4A and one, stage 5) had rhegmatogenous components. Among 14 infants followed up for more than three months, four developed nystagmus, and six developed strabismus. In contrast to cryoablation, diode-laser photoablation of the peripheral retina was found to be an effective treatment for threshold retinopathy of prematurity located in zone 1. Portability and ease of use of the laser system, precision of treatment, and minimal postprocedural adnexal inflammation are further advantages of this therapeutic modality.