Wearable sensors are revolutionizing personalised healthcare and have continuously progressed over the years in both research and commercialization. However, most efforts on wearable sensors have been focused on tracking movement, spatial position and continuous monitoring of vital signs such as heart rate or respiration rate. Recently, there is a demand to obtain biochemical information from the body using wearables. This demand stems from an individuals’ desire for improved personal health awareness as well as the drive for doctors to continuously obtain medical information for a patients’ disease management. Epidermal sensors are a sub-class of wearable sensors that can intimately integrate with skin and have the potential for monitoring physical changes as well as detecting biomarkers within skin that can be related to human health. The holy grail for these types of sensors is to achieve continuous real-time monitoring of the state of an individual and the development of these sensors are paving the way towards personalised healthcare. However, skin is highly anisotropic which makes it challenging to keep epidermal sensors in consistent contact with skin. It is important that these sensors remain in contact with skin in order to measure its electrical properties and acquire high fidelity signals. The key objective of this thesis is to develop thin conformable, stretchable epidermal sensors for tracking changes in skin physiology. The initial iteration of the screen printed epidermal sensor comprised of a flexible silver film. Impedance spectroscopy was used to understand the electrical signals generated on skin and it was used to measure relative changes due to varying water content. However, this iteration was more suited for single use. The next chapters explore different ink formulations and adherence methodologies to enhance the epidermal sensors adherence to skin. Impedance spectroscopy was used to characterise the electrical signals from these different epidermal sensor iterations, while tensile testing and on-body assessment was used to characterise its mechanical properties. The final chapter focused on investigating the use of phenyl boronic acid (PBA) functionalized hydrogels to modify the epidermal sensor with responsive hydrogel materials to enable chemical sensing of analytes relevant to skin physiology. Impedance spectroscopy was used to characterise and understand the electrical signals generated by the binding interaction of the PBA and analytes using the sensor. Overall, the work demonstrates the challenges of developing these epidermal sensors as well as presenting their potential for continuous monitoring of human skin in the future.