Ninety-six low birth-weight premature infants at risk of retinopathy of prematurity (ROP) were screened over a 25-month period, yielding 30 eyes of 15 infants with 'treatable' disease. The response and complications of cryotherapy were prospectively evaluated in these infants over a 3-24-month period. Six eyes of three infants progressed to cicatricial disease despite treatment. One infant developed angle closure glaucoma but neither eye showed cicatricial disease. In 24 eyes of 12 infants regression of active ROP was observed after treatment. The local and systemic complications associated with cryotherapy are discussed.