Of the 96 babies born at less than 30 weeks gestation at Westmead Hospital between January 1986 and December 1987, 91 were studied. Of these 37 developed some form of retinopathy of prematurity (ROP), with eight babies having stage 3 or worse. We compared the clinical features of these eight babies to a control group of eight babies with stage 2 ROP, having matched for gestational age. Factors of statistical significance in progression beyond stage 2 were male sex and number of days of assisted ventilation. The presence of a patent ductus arteriosus, although not statistically significant, is a factor which we consider to be clinically important. The development of Plus disease is associated with a poor prognosis.