Random mutagenesis or genetic modification of an organism without consideration of its consequences to the entire system might cause unwanted changes in cellular metabolism. Systems metabolic engineering thus aims to develop strains by performing metabolic engineering within a systems biology framework, in which entire cellular networks are optimized and fermentation and downstream processes are considered at early stages. Thus, regulatory, metabolic and other cellular networks are engineered in an integrated manner. Here, we review the applications of systems biology for the development of strains and bioprocesses by means of several successful examples and, furthermore, discuss future prospects.