Introduction - The Indian Ocean Epidemiological Surveillance Network (REVE) is a network established in 1996 for the exchange of epidemiological data on infectious diseases among the islands of the southwestern Indian Ocean. The objectives of this study are to describe the data received during the regional chikungunya epidemic in 2005–2006 and to highlight the benefits and limitations of this type of network in this context. Method - It consisted of analyzing weekly reports from network members, which includes five territories in the southwestern Indian Ocean region as well as one partner, Mayotte. The network is based on the exchange of aggregated data on infectious diseases in these territories. The data comes from the network’s focal points and from the monitoring of informal signals. The coordination—which involves receiving, following up on, synthesizing, and disseminating the data—is carried out by the Regional Health Observatory (ORS) of Réunion. Results—From January 1, 2005, to July 31, 2006, 191 weekly chikungunya reports were received. These data were heterogeneous and incomplete. However, several early warning signals circulated within the Reve network prior to the identification of the causative agent, allowing correspondents to be alerted in advance to outbreaks later confirmed as chikungunya. Discussion - In the context of a regional chikungunya epidemic, Reve demonstrated the utility of such a network for the exchange of epidemiological data in the Southwestern Indian Ocean region. However, the lack of an alert response function prevented the implementation of appropriate interventions. The evolution of this network into a system supporting epidemiological surveillance and epidemic investigation, in line with the new International Health Regulations, is highly desirable. (R.A.)