The reprogramming of human somatic cells to induced pluripotent stem (iPS) cells has offered the �opportunity to derive patient-specific cells with embryonic stem cell (ESC) properties. Human iPS cells demonstrate the ability to self-renew and to differentiate into any cell type of the body. They provide vast opportunities for in vitro modeling of development and disease and have the potential to be a source for cell replacement therapies. This protocol describes the culture and reprogramming of primary human fibroblasts from skin biopsies using retroviral transduction of OCT4, SOX2, KLF4, and c-MYC with the addition of the histone deacetylase (HDAC) inhibitor, valproic acid (VPA). Characterized patient-specific iPS cell lines can be obtained within a period of 2–3 months.
