Ham's F-12 Nutrient Mixture (F-12) was designed for serum-free single-cell plating of Chinese Hamster Ovary (CHO) cells. F-12 has since been used for serum-free growth of CHO cultures as well as serum-supplemented growth of other mammalian cells, including chondrocytes and rat prostate epithelial cells. We offer a variety of Gibco F-12 modifications for a range of cell culture applications.