A seroepidemiological survey for the assessment of immunity against polioviruses and non-polio enteroviruses (NPEV) seroprevalence was performed using a recently established automated microneutralization assay. The seroprevalences of neutralizing antibodies against Coxsackie viruses B1-B6, and A9, echoviruses 6, 9, 11, and 30, and polioviruses 1, 2, and 3 were investigated in serum samples collected over a period of 30 months (January 1990 to June 1992). Overall, NPEV seroprevalence ranged from 8.3% (Coxsackie virus B6) to 69.8% (echovirus 30). Age-related increases of seroprevalence were only observed for Coxsackie viruses B2 and A9. Relatively low antibody titres were found, the average antibody titre being the highest for Coxsackie virus B2 (1/55.4). The overall poliovirus seropositivity rate reached 80%. The highest seroprevalence was observed in the higher age groups (> or = 50 years). A relatively high proportion (7%) of individuals did not show neutralizing antibodies against all the three poliovirus serotypes. The results of our study have shown that, using an automated microneutralization assay, it is possible to perform seroepidemiological surveys in large patient populations. Until now, no comparable study concerning the NPEV seroprevalence has been performed.