Growth failure is a common and complicated process in children with cystic fibrosis (CF). Growth hormone, which is becoming a more commonly used agent in such patients, has demonstrated beneficial effects aside from increased growth velocity. Recently, insulin-like growth factor-1 has gained significant attention in the understanding of growth failure in children with CF. We report the successful prolonged use of recombinant human insulin-like growth factor-1 in an adolescent boy with CF, who demonstrated significant clinical benefits from the therapy. Pediatr. Pulmonol. 2011; 46:1137-1141. (c) 2011 Wiley Periodicals, Inc.