We report on six cases of leptospirosis observed in fifteen years in our department of nephrology. The contamination is two times from professional origin and four times linked to water leisures, during hot season, from june to september for the majority. Two serotypes are found: L. icterohaemorragiae characterized by marked jaundice, and L. patoc with anicteric form. Acute renal failure, five times oliguro-anuric, necessitates in the six cases hemodialysis (two to six sessions). Meningitis is found in four patients, associated in one case to an encephalitis and a polyradiculoneuritis. In one case, there were interstitial pulmonary lesions, in one another, a myocarditis with conduction disorders, responsible of the only death of this series, and finally, in three cases, a gastrointestinal hemorrhage. Bacteriological diagnosis seems little profitable and microagglutination remains the reference technique, helped by the IgM detecting through ELISA, looking forward to the evaluation of PCR (Polymerase Chain Reaction).