This chapter deals with biobased biodegradable polyurethane (PU) and its nanocomposites as biomaterials. The chapter also describes the importance of biodegradable biomaterials and the role of nanomaterials on the ultimate performance of such biomaterials. The characterization techniques related to the biological attributes of the above polymer nanocomposites are also briefly demonstrated herein. Physico-mechanical and biological properties of the nanocomposites are also described in this chapter. Finally, the chapter emphasizes various applications of PU and its nanocomposites as biodegradable biomaterials. The conclusions and future trends in the topic are highlighted at the end of the chapter.