Introduction. -Leptospirosis is a worldwide zoonosis caused by pathogenic species of the genus Leptospira. This infectious disease known with a high incidence in Reunion island (French overseas territories in Indian Ocean) is in state of endemia especially during rains season. Objectives. -The aim of our work was to identify the mains epidemiologic, clinical, biological, and therapeutic features of leptospirosis in children. Population and methods. -We conducted a retrospective analysis of children hospitalized in pediatric unit with the diagnosis of leptospirosis from January 2001 to June 2004 in general hospital of Saint-Denis. We found out 16 cases (mean age 14 years, range 9-17), mainly boys (ratio 7:1). Results. -The patient sera reacted most strongly with Leptospira interrogans serovars canicola (66% ), icterohaemorrhagiae (17% ), and sejroe (17% ). Epidemiologic data indicated contact with contaminated water in most cases (68% ). Jaundice was present in 43% of the patients, increased transaminase levels in 56% , renal failure in 50% , meningitis in 25% , ECG abnormalities in 6% , respiratory manifestations in 6% , systemic manifestations in 12% and thrombocytopenia in 56% . Death rate was zero, but renal failure is likely to induce life prognosis. Discussion. -The diagnosis’ traps are numerous, leading to an underestimation and underdiagnosis of the leptospirosis, more over there is a lack in specific, reliable, and quick biological test to make the diagnosis. A negative polymerase chain reaction analysis (PCR) do not exclude the diagnosis, and the microagglutination test (MAT) remains the reference of the undoubtly diagnosis of leptospirosis. It appears that it is more often the conjunction of epidemiologic data (young boy, swimming or fishing in river, rains season), with clinical and biological data that lead to the diagnosis. Diagnosis was not evoked at the emergency room in 37% of the patients. Conclusion. -Leptospirosis should be considered face to an influenza like illness especially during rains season. Introduction. -Leptospirosis is a worldwide zoonosis caused by pathogenic species of the genus Leptospira. This infectious disease known with a high incidence in Reunion island (French overseas territories in Indian Ocean) is in state of endemia especially rains season. Objectives. -The aim of our work was to identify the mains epidemiologic, clinical, biological, and therapeutic features of leptospirosis in children. Population and methods. -We conducted a retrospective analysis of children hospitalized in pediatric unit with the diagnosis of leptospirosis from January 2001 to June 2004 in general hospital of Saint-Denis. We found out 16 cases (mean age 14 years, range 9-17), mainly boys (ratio 7: 1). Results .- The patient severely depressed with Leptospira interrogans serovars canicola %), icterohaemorrhagiae (17%), and sejroe (17%). Epidemiologic data indicated contact with contaminated water in most cases (68%). Jaundice was present in 43% of the patients, incr eased transaminase levels in 56%, renal failure in 50%, meningitis in 25%, ECG abnormalities in 6%, respiratory manifestations in 6%, systemic manifestations in 12% and thrombocytopenia in 56%. Death rate was zero, but renal failure is likely to induce life prognosis. Discussion. -The diagnosis’ traps are numerous, leading to an underestimation and underdiagnosis of the leptospirosis, more over there is a lack of specific, reliable, and quick biological test to make the diagnosis. A negative polymerase chain reaction analysis (PCR) do not exclude the diagnosis, and the microagglutination test (MAT) remains the reference of the undoubtly diagnosis of leptospirosis. It appears that it is more often the conjunction of epidemiologic data (young boy, swimming or fishing in river, rains season), with clinical and biological data that lead to the diagnosis. Diagnosis was not evoked at the emergency room in 37% of the patients. Conclusion. -Leptospirosis should be considered to an iinfluenza like illness especially during rains season.