Dengue is an arbovirus disease caused by a Flavivirus and transmitted by mosquitoes of the genus Aedes, which have been present in certain departments in southeastern France since 2005. Since July 2006, dengue has been a notifiable disease in France (except in the French departments of the Americas). This study presents the cases reported in mainland France from July 1, 2006, to December 31, 2008. Method - Cases subject to mandatory reporting are defined as a sudden onset of fever > 38.5°C, lasting less than 7 days, in the absence of any identifiable source of infection, with at least one pain-related symptom and one of the following positive laboratory findings: RT-PCR or IgM. Cases diagnosed more than 7 days after the onset of reported symptoms were included in the analysis if they had been present the day before or at least one of the 7 days following the onset of symptoms in the country. Results - 132 cases were validated, all imported. All were potentially viremic, but 39% (n=52) were diagnosed more than 7 days after symptom onset. The median age was 40 years. Four patients presented with dengue hemorrhagic fever. Cases returned mainly from the French West Indies (41%) and Asia (27%). Of the 12 patients diagnosed between May 1 and November 30 in a department where the vector is established, 7 did not meet the DO criteria. Conclusion - The DO criteria exclude potentially viremic cases in mainland France, even though these cases require vector control measures to prevent the establishment of an indigenous transmission cycle. These criteria must therefore be modified. (R.A.)