ANAMNESIS:In winter, a 37-year old male patient consulted our outpatient clinic complaining about fever, malaise and headache. He had returned from vacation in Thailand 14 days earlier. EXAMINATIONS:Clinical findings, laboratory examinations and apparative diagnostics revealed a pulmo-renal syndrom accompagnied by multi-organ failure. DIAGNOSIS:Finally, we could confirm that our patient suffered from leptospirosis. TREATMENT:The patient received a penicillin-based antibiotic treatment. CLINICAL COURSE:Two days after presentation, the patient had to be transferred to the intensive care unit. Noninvasive respiratory support and hemodialysis helped to stabilize the patient. Finally, the patient could be discharged after four weeks in the hospital. CONCLUSION:Taking into account the seasonal accumulation of flu-like symptoms in winter and the patient's stay in a tropical region, differential-diagnostics were challenging in this case. Leptospirosis often presents as pulmp-renal syndrome.