Chikungunya fever is an acute febrile illness associated with severe, often debilitating polyarthralgias. The disease is caused by Chikungunya virus (CHIKV), an arthropod-borne virus that is transmitted to humans primarily via the bite of an infected mosquito. Since a re-emergence of CHIKV in 2004, the virus has spread into novel locations, such as Europe, and has led to millions of cases of disease throughout countries in and around the Indian Ocean. The risk of importation of CHIKV into new areas is ever present because of the high attack rates associated with the recurring epidemics, the high levels of viremia in infected humans, and the worldwide distribution of the vectors responsible for transmitting CHIKV. In this review, we will characterize the epidemiology and global expansion of CHIKV, describe the clinical features and laboratory testing for the disease, and discuss priorities for further studies needed for effective disease control and prevention.