The occurrence of encephalomyocarditis virus (EMCV) among domestic pigs and wild boar in several European countries is described and discussed. From 1990 to 2001 clinical outbreaks were analysed and serum samples, partly from existing screening programmes, were tested for antibodies against EMCV. Most clinical EMCV outbreaks were reported in Belgium (320), followed by Italy (110), Greece (15) and Cyprus (6). The outbreaks appeared to be clustered in ‘endemic areas’ with an increase in outbreaks during the autumn and winter months. The within-herd seroprevalence measured in clinically affected pig farms varied considerably among farms (2–87%), with age (0–84%) and by country. Data from farms with no clinical disease showed that subclinical infection with EMCV was found both within (seroprevalence 6–62%) and outside (up to 17%) the endemic areas of the clinically affected countries as well as in the non-clinically affected countries Austria and France (3–5·4%). Among wild boar, the seroprevalence varied between 0·6 and 10·8%, and a study in Belgium found a prevalence of virus infection of 3·3%.