In this chapter, we present the recent developments in the field of wearable bioelectronics with emphasis on the design of flexible and stretchable sensors for health-care applications. It is one of the key challenges to construct a flexible sensor which can be conformably mounted on the soft and curvilinear surface of human skin for physiological signal monitoring with ideal accuracy and sensitivity. This chapter summarizes the recent process of various design strategies as well as working principles in materials and configurations aspect of flexible and stretchable sensors. In addition, wearable sensors for continuously monitoring physiological signals including physical signs and biochemical biomarkers are presented. Future perspectives of wearable bioelectronics are also briefly discussed.