Wearable devices are becoming ubiquitous. They are used extensively by consumers and are becoming more noticeable in the medical domain. But contemporary wearable devices are still relatively bulky and often have limited equivalence to medical gold standards. Skin patches with chemical, mechanical, and electrophysiological sensors offer new opportunities for future sensors. These devices can be designed to seamlessly interact with the user while also providing high quality and long-term data. In combination with miniaturized low power electronics and powerful data analysis algorithms these devices have the potential to provide continuous measures of various physiological parameters from freely behaving humans. In this presentation I will present the state of the art in the field, focusing on some of our recent achievements and challenges in monitoring the electrophysiology of freely behaving humans.