Traditionally, the implantation of stents in young children with small blood vessels has been avoided as the presence of a metallic or fixed stent structure limits the ability to further dilate the stent with vessel growth. Pulmonary atresia with ventricular septal defect and hypoplastic pulmonary arteries represents one such cohort where the placement of fixed nondegradable stents has been difficult. We report a 2-month-old girl with pulmonary atresia, VSD, and multiple aorto-pulmonary collaterals with severely hypoplastic pulmonary arteries who underwent placement of a biodegradeable magnesium stent within a stenotic aorto-pulmonary collateral. Although there was an initial significant increase in vessel diameter, significant restenosis occurred 4 months after stent placement. This to our knowledge represents the first case of the use of biodegradable stents in a child with severely hypoplastic pulmonary arteries. Although further refinements in stent technology are required, this development will hopefully usher in a new era of potential intervention in children previously deemed unsuitable for stent placement. (C) 2007 Wiley-Liss, Inc.