Age is an important attribute of human beings. In recent years, automatic estimations of the user’s age have been becoming an active topic in pattern recognition, computer vision, voice recognition, human-computer interaction (HCI), etc. It can be widely used in many real applications such as forensics, e-business, security, and so on. In daily life, people can easily estimate the age of a person according to some visual and audio information (here mainly refers to face and voice) because humans’ faces and voices are important agents of their age. This paper introduces in detail the models, algorithms used in automatic age estimation based on visual and audio information, as well as their performance and characteristics. The possible future directions for the research in automatic age estimation are also discussed.