A unit-dose system was designed to dispense precise quantities of blood in a form ready for immediate transfusion into neonatal patients. The principles were similar to those used by pharmacies to dispense individual doses of drugs. In the blood center, the precise volume of blood ordered for a neonatal patient was aspirated through a microaggregate filter into a labeled plastic syringe for dispensing to the nursery in a correspondingly labeled zip-lock plastic bag. In the nursery, the premeasured and prefiltered blood was ready for immediate infusion, and the syringe was attached directly to a mechanical infusion pump. Several experiments were performed to ensure sterility and quality of whole blood dispensed by this system. Over 300 aerobic and anaerobic cultures were performed, and it was concluded that the extra handling required to prepare syringes of blood did not lead to bacterial contamination. In addition, the quality of whole blood was maintained, for at least 6 hours, equally well in syringes as it was in blood bags stored under standard blood bank conditions when assessed by hematocrit, blood pH, and measurements of plasma potassium, glucose, lactic dehydrogenase, and free hemoglobin. Thus, unit dose dispensing offers a precise and convenient method to prepare small, accurately measured quantities of filtered, sterile, and quality blood products for neonatal patients.