The fabrication of multifunctional epidermal electronic devices capable of efficiently reading electrophysiological signals and converting low-amplitude mechanical signals into electric outputs promises to pave the way towards the development of self-powered wearable sensors, smart consumer electronics, and human-machine interfaces. This article describes the scalable and cost-effective fabrication of epidermal, nanotexturized, triboelectronic devices (EnTDs). EnTDs can be conformably worn on the skin and efficiently monitor electrophysiological signals, temperature, and hydration levels. EnTDs, while measuring electrophysiological signals, can also convert imperceptible time-variant body motions into electrical signals using a nanotexturized triboelectric layer, enabling the self-powered monitoring of respiration, swallowing, and arterial pulse. These results suggest the potential of EnTDs as a new class of multifunctional skin-like sensors for biomedical monitoring and self-powered sensing applications.