Vascular access in young children frequently proves difficult in the prehospital setting. To assess the feasibility of training paramedics in the placement of intraosseous (IO) lines as an alternative to intravenous (IV) access, this pilot project studied a training program and treatment protocol for prehospital IO use. Paramedics underwent a training program in IO placement. Patients enrolled were less than five years of age and in cardiac arrest. During a 10-month period, paramedics attempted 12 IO placements, of which 10 (85%) were successful, nine on the first attempt. Although no patients achieved long-term survival, three were initially resuscitated from arrest. Paramedics can be trained in IO placement, and IO infusion can be used in prehospital pediatric care. Training methods, limitations, and implications for future use are discussed.