Injectable fillers for both bone and soft-tissue are used for a range of medical applications from aesthetic rejuvenation through space filling to functional restoration of structural tissues. Fillers can be classed as biological, synthetic, biosynthetic or composite materials on the basis of their primary components. Most commonly used in practice are the biological fillers such as collagen and hyaluronic acid, however synthetic and biosynthetic fillers are the topic of intense research and patenting activity. Composite fillers are typically used in bone filling applications with hydroxyapatite ceramic components being combined with synthetic or biological carrier polymers. More recent patenting activity appears to focus on biosynthetic and composite fillers with some patents proposing that cell incorporation in some of these fillers is a possible approach to improving their performance. The next challenge will be in translating new ideas for biosynthetic and composite fillers as well as fillers incorporating functional cells into engineered medical products.