Artificial Intelligence is driving a new revolution in domains ranging from manufacturing, automotive, healthcare, robotics, entertainment, and many others. New computing platforms are required to support the emerging AI algorithms and applications, from cloud servers to edge devices, from system level to circuit level. The IEEE International Conference on Artificial Intelligence Circuits and Systems facilitates research, innovation, and development activities at the frontiers of circuits and systems for Artificial Intelligence. It allows academia to meet industry from the international community to exchange experiences, demonstrate their studies, and further advance AI technologies. AICAS is the major conference for AI that stands between theory, applications, and ASICs. AICAS2021 brings together members of AI and CAS communities to broaden their knowledge and create synergies between applications and their supporting hardware.