This study demonstrates the efficient generation of human hepatocyte-like cells from induced pluripotent stem (iPS) cells, addressing the global shortage of donor livers for orthotopic liver transplant (OLT) and hepatocyte transplantation therapies. The authors show that mouse iPS cells can generate fetal livers in vivo, and they describe a protocol for producing highly differentiated hepatocyte-like cells from iPS cells that display key liver functions and can integrate into the hepatic parenchyma in vivo. The protocol involves defined culture conditions, eliminating the use of serum, fibroblast feeder cells, embryoid bodies, and undefined culture medium components. Both human embryonic stem (huES) cells and human iPS cells (hiPS) were used to generate hepatocyte-like cells, with similar efficiency and differentiation characteristics. These cells exhibited markers of hepatocytes, including albumin expression, and demonstrated hepatic functions such as glycogen synthesis, lipid accumulation, LDL uptake, and urea metabolism. Additionally, the differentiated cells were morphologically similar to primary hepatocytes and could be integrated into the mouse liver parenchyma. The study highlights the potential of iPS cells as a source of patient-specific hepatocytes for therapeutic and research purposes.This study demonstrates the efficient generation of human hepatocyte-like cells from induced pluripotent stem (iPS) cells, addressing the global shortage of donor livers for orthotopic liver transplant (OLT) and hepatocyte transplantation therapies. The authors show that mouse iPS cells can generate fetal livers in vivo, and they describe a protocol for producing highly differentiated hepatocyte-like cells from iPS cells that display key liver functions and can integrate into the hepatic parenchyma in vivo. The protocol involves defined culture conditions, eliminating the use of serum, fibroblast feeder cells, embryoid bodies, and undefined culture medium components. Both human embryonic stem (huES) cells and human iPS cells (hiPS) were used to generate hepatocyte-like cells, with similar efficiency and differentiation characteristics. These cells exhibited markers of hepatocytes, including albumin expression, and demonstrated hepatic functions such as glycogen synthesis, lipid accumulation, LDL uptake, and urea metabolism. Additionally, the differentiated cells were morphologically similar to primary hepatocytes and could be integrated into the mouse liver parenchyma. The study highlights the potential of iPS cells as a source of patient-specific hepatocytes for therapeutic and research purposes.