Among 1158 preterm infants of 29-35 weeks' gestational age, respiratory syncytial virus (RSV) -related hospitalizations (RSV-H) occurred in 4.2% during the first year of life. Four independent factors influenced the risk for RSV-H: neurologic problems (odds ratio [OR], 3.6), male gender (OR, 2.8), presence of an older sibling (OR, 1.7) and discharge from October to December (OR, 1.7). The estimated risk of RSV-H varied between 1% (no risk factor present) and 30% (4 risk factors present).