Background: The first case of dengue fever was diagnosed in May 2019 in the Atlantic department of Be-nin. From April 26 to July 29, 2019, the epidemic reached the Littoral and Ouémé depart-ments. We conducted this study to determine the scale of the epidemic in order to put in place prevention and control measures. Methods: We conducted a transversal descriptive study by examining the surveillance data in the health districts having notified the cases in the three (03) departments. The cases of dengue were identified according to the definition of the cases developed. We reviewed the Medical case files, hospital registers and dengue case reports. A question-naire was administered to patients in health facilities and at home. Results: Out of 30 suspected cases of dengue fever, 08 were confirmed, of which 02 died. The median age was 26.5 years IIQ22 to 32 years. The departments of Atlantic and Littoral recorded re-spectively 13,3% and 83,3% of confirmed notified. The average time to hospital admission for patients was 4 days (0-10 days). All of the cases reported sleeping under mosquito nets at night but not during the day and that their living environment contains water receptacles. The time to hospital admission for the index case and confirmation was 1 day. Conclusion: Benin experienced its first dengue epidemic in 2019. Strengthening dengue surveillance through weekly case reporting from all public and private health facilities is necessary for disease control in Benin.

Keywords: Investigation epidemic dengue