Leptospirosis is a widespread and potentially fatal zoonosis that is endemic in many tropical regions. It is the most common zoonotic infection in the world, but a rare disease in Latvia. The clinical manifestations and the severity of leptospirosis are highly variable. This case report describes a 64-year-old male without comorbidities, who was admitted to Rīga East University Hospital in the Gastroenterology Department due to expressed jaundice, weakness, and acute kidney injury. The initial inpatient clinical diagnosis was initially acute alcoholic hepatitis, as the patient had consumed alcohol a month before hospitalisation. The clinical and laboratory picture of the patient was dominated by significant hyperbilirubinemia, a relatively small increase in liver transaminases, preserved synthetic liver function, acute kidney failure in the polyuria phase, and severe thrombocytopenia. During hospitalisation, the study of anamnesis and the results of laboratory tests gave grounds for suspecting the diagnosis of leptospirosis, which was subsequently serologically confirmed. Routine laboratory tests are not specific for diagnosing leptospirosis. Diagnosis is made on the basis of the doctor’s request and clinical examination, as well as on the basis of blood and urine culture and serological tests. Early initiation of antibiotic therapy plays an important role in controlling infection and reducing mortality.