Tick-borne encephalitis (TBE) is the most common viral disease transmitted by ticks in Poland. The exact number of cases is significantly underestimated due to the fact that patients presenting with infectious diseases and signs of the involvement of the central nervous system are rarely tested for TBE. The symptoms of tick-borne encephalitis are non-specific. Determination of the blood serum concentration of TBE antibodies should be considered in patients who develop the disease in June–October and have a positive history of tick bite. Better detection of TBE infection would make it possible to reduce the number of tests performed and the amount of pharmacotherapy applied, including unnecessary antibiotic therapy.