A large chikungunya virus (CHIKV) outbreak emerged in 2005-2006 in the Indian Ocean islands, including Comoros, Mayotte, Mauritius, the Seychelles, and particularly in Reunion Island where 35% of 770,000 inhabitants were infected in 6 months. More recently, circulation of the virus has been documented in Madagascar and in India where CHIKV is spreading rapidly. CHIKV-infected visitors have returned home to nonendemic regions from these islands. We conducted a 14-month prospective observational study on the clinical aspects of CHIKV infection imported to Marseilles, France, in travelers returning from the Indian Ocean islands. A total of 47 patients have been diagnosed with imported CHIKV infection confirmed by serology, reverse transcription-polymerase chain reaction, and/or viral culture. At the early stage of the disease (within 10 days of the disease onset), fever was present in 45 of 47 patients. A rash was present in the first week in 25 cases. All patients suffered with arthritis. The most frequently affected joints were fingers, wrists, toes, and ankles. Eight patients were hospitalized during the acute stage, including 2 severe life-threatening cases. A total of 38 patients remained symptomatic after the tenth day with chronic peripheral rheumatism, characterized by severe joint pain and multiple tenosynovitis, with a dramatically limited ability to ambulate and carry out activities in daily life. Three patients were hospitalized at this stage for severe persistent handicap. Follow-up demonstrated slow improvement in joint pain and stiffness despite symptomatic treatment, mainly antiinflammatory and analgesic drugs. In the current series we describe 2 stages of the disease, an initial severe febrile and eruptive polyarthritis, followed by disabling peripheral rheumatism that can persist for months. We point out the possibility of transitory peripheral vascular disorders during the second stage and the occasional benefit of short-term corticosteroids. As CHIKV could spread throughout the world, all physicians should be prepared to encounter this arboviral infection.