BACKGROUND: Retinopathy of prematurity (ROP) is a cause of neurosensorial morbidity. OBJECTIVES: To study the incidence, associated risks factors, treatment, and outcome of ROP in premature infants born at less than 32 weeks in our hospital. METHODS: We performed a descriptive study of patients born between the January 1, 1995, and December 31, 2001, in Sant Joan de Déu Hospital in Barcelona (Spain) at <= 32 weeks of gestation who survived until their first month of life. An ocular evaluation was performed between weeks 4 and 6 of life and was repeated every 1-2 weeks until retinal vascularization was complete. Ocular sequelae and visual function were evaluated. Bivariate comparison of groups with and without ROP was performed. RESULTS: Of the 324 patients evaluated, 74 presented ROP (22.8 %), of which 63 patients (21.7 %) were classified as stage 1 or 2 and 11 (3.7 %) as stage 3. An inverse correlation between the incidence of retinopathy and weight and gestational age was found. Threshold disease (3 plus) was detected in 9 patients (16 eyes; 3.1 % of the study sample and 12.1 % of the neonates with retinopathy). All of these neonates were treated with laser therapy. Ocular sequelae were mild in 2.7 % of the patients, moderate in 0.6 % and severe in 0.6 %. The visual function (n 236) of infants with ROP (n 74) was altered in 4 patients (1.7 %). Of these, alterations were severe in 2 patients (0.8 %). Bivariate analysis revealed significant differences (p < 0.001) in low birth weight, gestational age, days of oxygen therapy, days of mechanical ventilation, days of antibiotic therapy, and number of blood transfusions. CONCLUSIONS: In this study the incidence of ROP was similar to that in other centers. Development of ROP was strongly associated with its various risk factors. Severe stages were not seen above 30 weeks of gestational age. The results of laser therapy were optimal, with fewer alterations in ocular examination and visual function than those estimated in patients without treatment.