The advances in cell culture engineering science have played a major role in the rapid expansion of mammalian cell-based products in the last decade. The host cell lines frequently used in manufacturing have converged to only a few species. For some, the genome has been completely sequenced. For others, the genomic sequence of closely related species is available, or will soon be available. The genomic and proteomic research tools enable one to globally survey the alterations at mRNA and protein levels to discover both primary and collateral gene expression changes and to unveil their regulation. Undoubtedly, a better understanding of these cellular processes at the molecular level will lead to a better strategy for "designing" producing cells and for process optimization. Herein the genomic and proteomic tools are briefly reviewed and their impact on cell culture Engineering is discussed.