The liver has a large capacity for regeneration after resection. However, below a critical level of future liver remnant volume (FLRV), partial hepatectomy is accompanied by a significant increase of postoperative liver failure. There is accumulating evidence for the contribution of bone marrow stem cells (BMSCs) to participate in liver regeneration. Here we report on three patients subjected to intraportal administration of autologous CD133+ BMSCs subsequent to portal venous embolization of right liver segments, used to expand left lateral hepatic segments as FLRV. Computerized tomography scan volumetry revealed 2.5-fold increased mean proliferation rates of left lateral segments compared with a group of three consecutive patients treated without application of BMSCs. This early experience with portovenous application of CD133+ BMSCs could suggest that this novel therapeutic approach bears the potential of enhancing and accelerating hepatic regeneration in a clinical setting.