Objective: Our purpose was to increase the number of the progenitor cells in umbilical cord blood collected for transplantation. Study Design: We randomly assessed the effect of “upper” and “lower” positions of the newborn on the volume and progenitor cell (CD34⁺) content of the umbilical cord blood collected from 49 healthy, vaginally delivered, term neonates. Results: Twenty-two collections were performed in the “upper” and 27 in the “lower” position. The volume of umbilical cord blood obtained in the “upper” position was 108.1 ± 19.1 mL compared with 42.6 ± 19.5 mL in the “lower” position (P < .0001). Mononuclear cell separation revealed significantly higher numbers of cells in umbilical cord blood obtained in the “upper” group (P < .01). Although the percentage of CD34⁺ cells was comparable, the absolute number of CD34⁺ cells was significantly higher in the “upper” group because of the larger volume collected (P < .02). At 24 hours after delivery the hemoglobin levels were not significantly different between newborns of the 2 groups. Conclusions: Placing the newborn on the maternal abdomen after delivery and before cord clamping may significantly increase the volume of umbilical cord blood collected and therefore the CD34⁺ counts that improve transplantation success without placing the mother or the newborn at risk. (Am J Obstet Gynecol 1999;180:1240-3.)