The development of microfabricated devices manufactured in silicon, glass, or plastic materials is a well-known trend in the research of novel biological techniques and tools over the last two decades, resulting in a multitude of start-up companies serving the pharmaceutical, biotechnology, and diagnostics markets. However, the idea of implementing such devices on microelectronic substrates has been introduced only recently. This chapter aims to describe the state-of-the-art of microsystems for molecular and cell biology produced in general purpose CMOS (complementary metal oxide semiconductor) technology, emphasizing the advantages of this approach along with their challenges and limitations. This chapter discusses significant examples of fully tested devices in comparison with existing state-of-the-art techniques.