Vascular access during advanced life support is essential. Vascular access in the critically ill child can be particularly difficult and often causes unacceptable delay. Intraosseous infusion provides safe, rapid, reliable access to the venous circulation. A case is presented illustrating the value of familiarity with this procedure. Use of the bone marrow for emergency administration of fluids and medications should be considered early in resuscitation until vascular access is obtained. © 1986.