Motivated by the occurrence of a case of suspected tick-borne meningoencephalitis (TBE) in a forestry worker of the Delnice Forestry Enterprise, 139 sera samples were collected from his co-workers, for TBE-specific IgG antibody testing. The commercially purchased ELISA and our own indirect immunofluorescence tests were used. Two sera samples were found positive and another six as inconclusive. All of them were sent for confirmation to the Institute of virology, University of Vienna. The two previously positive sera were also ELISA positive in Vienna, the rest being qualified as negative. Accepting that the first case really had TBE and that the two seropositives have experienced infection with the TBE virus, it is inferred that in the wider region of Delnice there is an until now unknown TBE focus, quiescent there for an unknown period of time.