The authors describe two cases of acute neuroborreliosis. The combined findings of these two differing cases serve as a reminder of certain aspects of the diagnosis of neuroborreliosis: the lack of erythema makes early detection difficult, the traditional concept of peripheral facial paralysis from the cold may delay cor- rect diagnosis, detailed examination of cerebrospinal fluid is the most important diagnostic tool in suspec- ted neuroborreliosis, absence of antibodies in the sérum does not rule out neuroborreliosis, IgG and IgM antibodies may persist for several years following successful treatment.

        Key words: neuroborreliosis, čase history, clinical diagnosis, serological diagnosis, ELISA, Western blot