PluriSTEM™ human ES/iPS medium is used for the expansion of human embryonic stem (ES) cells and induced pluripotent stem (iPS) cells in feeder- and serum-free conditions. The formulation includes Activin-A, TGFβ1, and b-FGF to promote stem cell self-renewal; small molecule combinations to inhibit unwanted spontaneous differentiation; and human serum albumin to aid in overall colony morphology. The culture of human ES/iPS cells typically requires feeding every day, including weekends. The PluriSTEM medium is designed to allow for feeding every other day, excluding weekends. It also provides high viability and proliferation rates in single cell passaging.