Retinopathy of prematurity (ROP) is one of the most important morbidity in premature infants. The latest American Academy of Pediatrics (AAP) screening guidelines for ROP are mandatory for infants with birth weights < or = 1500 g or gestational ages (GA) < or = 28 weeks. To determine the appropriate upper limits for ROP screening in Taiwan in terms of birth weight and gestational age, we performed a retrospective review of all 617 infants who were born at the National Taiwan University Hospital from January 1, 1994 to December 31, 1999, and survived beyond 28 days of life and received eye-ground evaluation under our current ROP screening guidelines. From the start of our study, the criteria for screening was birth weight <2000 g or gestational age < 35 weeks. The maximal stage of retinopathy observed was recorded. We found no ROP greater than stage I in infants with birth weights > 1500g and GA > 31 weeks. In comparing with our current guidelines, lowering the screening criteria to birth weight < or = 1500g or gestational age < or = 31 weeks reduced the number of infants requiring screening by 37.2%, while no case of ROP greater than stage 1 was missed. However, five cases of stage 2 ROP would have been missed in our study if the gestational age cut-off was < or = 28 weeks as recommended by AAP. Therefore, we recommend that in the tertiary nursery in Taiwan, the gestational age < or = 31 weeks or birth body weight < or = 1500 g should be screened for ROP regardless of clinical condition. The screening for larger infants with high risk of ROP requires further discretion of the attending physicians.