This book gathers the proceedings of the IV International Conference on Biomedical and Health Informatics (ICBHI 2019), held on 17-20 April, 2019, in Taipei, Taiwan. Contributions span a range of topics, including medical imaging, biosignal processing, biodata management and analytics, public and personalized health systems, mobile health applications and many more. The IV conference edition gave a special emphasis to cybersecurity issues and cutting-edge medical devices, as it is reflected in this book, which provides academics and professionals with extensive knowledge on and a timely snapshot of cutting-edge research and developments in the field of biomedical and health informatics.