Leptospirosis is a zoonotic disease of global reach caused by pathogenic spirochetes of the genus Leptospira. The disease has two periodic phases (septic and immune phase) and its clinical manifestations are diverse. Central nervous system involvement in leptospirosis most commonly occurs as aseptic meningitis, often asymptomatic, only with abnormal cerebrospinal fluid findings. Weil's syndrome is defined as liver damage with acute renal failure and bleeding diathesis, has a high mortality rate. A pulmonary form may occur as an acute respiratory distress syndrome. The reference standard assay is the microscopic agglutination test. A titer of at least 1:400 in the presence of symptoms confirms the diagnosis. The prognosis depends on a rapid identification and treatment with antibiotics. The paper presents selected cases of leptospirosis with its different clinical manifestations. The common feature was a severe illness and sometimes the need for cooperation of doctors of various specialities.