AIM: To investigate the incidence of retinopathy of prematurity(ROP) in the southern Brazil, the rate of treatment and outcomes in all premature infants born at Hospital de Clinicas de Porto Alegre, Brazil, from October 2002 to October 2006. · METHODS: A prospective cohort study was conducted on 323 premature children born at Hospital de Clinicas de Porto Alegre, Brazil, from October 2002 to October 2006 with birth weight equal to or less than 1 500g or a gestational age at birth of 32 weeks or less. All of the newborns were examined by indirect binocular ophthalmoscopy with the 28 diopters lens after pupil's dilation and a lid speculum after the sixth week of life with examinations repeated depending on the disease classification. The main clinical outcome was the occurrence of ROP at any stage. · RESULTS: ROP occurred in 82 infants with an incidence rate of 25.7%. Threshold disease occurred in only 17 of the patients (5.3%), all of them had the disease affecting posterior Zone II needing laser treatment. None of the treated children had Zone I or aggressive posterior disease despite that three of the treated children needed a second laser session. One patient of the re-treated group needed scleral buckling with an equatorial silicon band after progression to stage 4 of ROP. · CONCLUSION: The incidence of retinopathy and the threshold disease in this study was similar to the international results reported. This study showed a high survival rate (70.1%), high incidence of retinopathy, and high laser treatment necessity among newborns under 28 weeks of gestational age or under 1 000g of birth weight. This study drove attention about the no identification of any Zone I posterior disease in this cohort of patients.