Chinese hamster ovary (CHO) colls are used extensively in the bio loph pharmaceutical -industry to produce recombinant proteins that require post-transanslatic on modification for full biological functionality. Optimization of culture conditions for recombinant CHO cell lines presents challenges in light of the diverse nutritional requirements observed with different clonally derived cell lines. To adress this challenge we have taken advantage of new technologies (high throughput screening and state-of-the-art cell line engineering), advances in medium development (a library of diverse CHO media formulations containing both animal-component free and chemically defined formulations), and the application of sophisticated Design of Experiment (DOE) experimental design and analysis techniques to develop e new strategic approach to medium development. This article describes this new strategic process and documents its use to develop several optimized formulations for a humanized IgG-producing CHO cell line.