Porous silicon (PSi) is a promising biomaterial for a wide range of biomedical applications. There are several reasons for this accolade. Tunable porous structures can be fabricated with relative ease in large quantities. Degradation of PSi in vivo causes little to no adverse effect on surrounding tissue and the degradation product, orthosilicic acid, is rapidly cleared from the body. PSi has a large surface area that can be modified with a wide variety of readily available chemistries, including polymers, and permits therapeutic molecules to be loaded. Hence, PSi is currently being intensely investigated for drug delivery, cell culture and tissue engineering applications. This chapter briefly introduces PSi, its functionalization and use in polymeric composites. The challenges and requirements of PSi-based biomaterials are also discussed, along with reviews of specific applications of PSi-polymer composites in cell culture and tissue engineering. We conclude with our future vision for these biomaterials.