The introduction of pervasive and ubiquitous systems into everyday life pushes this technology to become increasingly embedded in artifacts and environments trying to address an important social and health care issue: as the world’s population ages, there is growing need for technologies to assist with the in-home care of the elderly and people with Alzheimer’s, Parkinson’s and numerous types of chronic disabilities or traumas. The quality of people’s living environments is particularly important in an increasingly crowded and complex world in which inclusiveness and connectivity with the rest of the world is critical. Furthermore, enabling such persons remain productive and active is of high socioeconomic importance to every country’s workforce or health care system. Assistive environments is a field that addresses the fact that, as people grow older or become disabled, they increasingly rely on computer technology to be able to live in and function in their homes [1–3]. Finally, assistive environments is a field that pushes innovation and interdisciplinary collaboration forward, catalyzes the union of computation with the development of new materials (e.g., sensors) and devices (e.g., assistive robots), new or improved drugs and drug administration, new methods and software for rehabilitation, physical/occupational therapy, new materials for safety or disorder monitoring (e.g., sleep disorders connected with epilepsy or depression), new algorithms for mental health and emotion monitoring (e.g., through facial expressions or speech), new types of virtual life coaches (e.g., avatars to promote exergaming) and many other innovations. This special issue comes after the successful organization of the 3rd and 4th International Conferences on ‘‘PErvasive Technologies Related to Assistive Environments—PETRA 2010 and 2011,’’ which were held in Corfu, Greece and Herakleion, Crete, Greece, respectively (http://www.petrae.org/). Both conferences received funding from the US National Science Foundation as well as support from the Hellenic National Center for Scientific Research—Demokritos and many other organizations. The focus of this special issue is how and what new technological innovations can assist and empower an elder or disabled human in everyday life. What technologies can assist specific health care needs, at home and at work, in a person’s everyday routine by using sensors, databases, personal area networks, ubiquitous connectivity, distributed intelligence and adaptive, easy to use interfaces and interactions. This special issue focuses on research involving the design, development, evaluation and use of emerging pervasive technologies for assistive environments for the disabled and the senior citizen, taking also into account the target audience of the PUC journal. The realization of pervasive health information applications through mobile devices introduces several challenges, such as (1) infrastructure for unified and ubiquitous access or medical data storage and management [4, 5], I. Maglogiannis (&) Department of Computer Science and Biomedical Informatics, University of Central Greece, Papasiopoulou 2-4, 35100 Lamia, Greece e-mail: imaglo@gmail.com; imaglo@ucg.gr