Rodent-borne hantaviruses (family Bunyaviridae, genus Hantavirus) cause hantavirus pulmonary syndrome in the Americas and hemorrhagic fever with renal syndrome in Europe and Asia. The viruses are transmitted to humans mainly by inhalation of virus-contaminated aerosols of rodent excreta and secreta. Classic clinical hemorrhagic fever with renal syndrome occurs in five phases: fever, hypotension, oliguria, polyuria, and convalescence. Hantavirus pulmonary syndrome is a severe acute disease that is associated with respiratory failure, pulmonary edema and cardiogenic shock. The diagnosis of hantavirus infections in humans is based on clinical and epidemiological information as well as laboratory tests. We review diagnosis for hantavirus infections based on serology, PCR, immunochemistry and virus culture.