This book constitutes the refereed proceedings of the Third International Workshop on Ambient Assisted Living, IWAAL 2011, held at IWANN 2011 in Torremolinos-Málaga, Spain in June 2011. The 30 papers presented were carefully reviewed and selected from numerous submissions. They are organized in topical sections on mobile proposals for AAL, applications for cognitive impairments, e-health, smart and wireless sensors, applied technologies, frameworks and platforms, and methodologies and brain interfaces.