Wearable electronics is one of the promising approaches for smart healthcare in near future. Various sensor-integrated wearable systems including dressable, accessary-like, skin-attachable or implantable platforms can monitor vital signs, detect biomarkers for disease diagnostics, and monitor the patients with chronic diseases and can be also used to detect the hazardous environmental factors around human with unobtrusiveness and pervasiveness. In particular, various physical, chemical and biological sensors with new functionalities such as flexibility, stretchability, optical transparency and conformality as well as stability and reliability against mechanical deformations are promising for skin-attachable platforms. In this presentation, stretchable physical sensors (strain, pressure, and temperature), chemical sensors (gas) and biosensors (metabolite, protein) based on low-dimensional nanoscale materials (0D, 1D and 2D), nanocomposites and their hierarchical nanohybrids in FETs, resistors or three-electrode electrochemical sensors are presented for applications to skin-attachable patches. In addition, some examples of patchable integrated platforms with multiple sensors or sensor-energy harvester-energy storage for monitoring of physiological parameters, emotional expressions, bodily motions, and daily activities of human are also presented.