In 2003, Dr Chan joined WHO as Director of the Department for Protection of the Human Environment. In June 2005, she was appointed Director, Communicable Diseases Surveillance. In September 2005, she was named Assistant Director-General for Communicable Diseases. Dr Chan was elected to the post of Director-General in November 2006. The Assembly appointed Dr Chan for a second five-year term in May 2012. Dr Chan's new term began in July 2012 and will continue until June 2017.