The authors reevaluate the components of human embryonic stem (ES) and induced pluripotent stem (iPS) cell culture and develop a chemically defined cell culture system. They remove serum albumin and β-mercaptoethanol from the existing medium (TeSR), creating a simplified E8 medium that supports the long-term proliferation of both ES and iPS cells. This medium is further optimized to improve the efficiency of iPS cell derivation from dermal biopsy samples using an episomal approach. Vitronectin-coated surfaces are also identified as effective for supporting cell attachment and survival in E8 medium. The E8 medium and defined conditions significantly enhance the efficiency of iPS cell derivation, demonstrating its potential for both research and clinical applications.The authors reevaluate the components of human embryonic stem (ES) and induced pluripotent stem (iPS) cell culture and develop a chemically defined cell culture system. They remove serum albumin and β-mercaptoethanol from the existing medium (TeSR), creating a simplified E8 medium that supports the long-term proliferation of both ES and iPS cells. This medium is further optimized to improve the efficiency of iPS cell derivation from dermal biopsy samples using an episomal approach. Vitronectin-coated surfaces are also identified as effective for supporting cell attachment and survival in E8 medium. The E8 medium and defined conditions significantly enhance the efficiency of iPS cell derivation, demonstrating its potential for both research and clinical applications.