Intraosseous infusion technique by paramedics in the prehospital setting was prospectively evaluated. Intraosseous access was successfully established in 16 of 17 pediatric patients with cardiopulmonary arrest. There were 13 successful first attempts with intraosseous access established within 1 minute. No significant complications occurred. In this study, the ease of establishing intraosseous access by paramedics in the field is documented.