Digitization of the healthcare sector has been a major impetus for rapid adoption of biometric technologies, ranking it only behind the financial sector in consumer facing applications. The highly critical nature of healthcare records, the legal and medical risks associated with mis-identification, and the requirement of quick access to user information makes biometrics a preferred technology. The body of research supporting the theoretical effectiveness and efficiency of biometric technologies is quite substantial but users, the deployment environment and the type of biometric technology heavily impact its actual effectiveness and efficiency. Biometric technologies open up unprecedented opportunities in ambient assisted living (AAL) applications, but they also raise some unanswered questions. The aim of this chapter is to provide its readers with a basic understanding of biometric technologies and processes, discuss research in this area, and future challenges and use of biometric technologies in the healthcare environment, and specifically AAL applications.