Reported are results of serologic examinations for the presence of anti-Toxoplasma antibodies by direct agglutination in 1,497 people: 1,327 forestry workers and 86 farmers occupationally exposed to T. gondii from the Lublin region (eastern Poland) and 84 inhabitants of the city of Lublin examined as the control group, including 50 blood donors and 34 workers from forestry headquarters. 58.5% positive results in forestry workers, 56.9% in farmers and 46.4% in the control group were obtained. The highest percentages of positive results were obtained in Sosnowica, Wlodawa and Sobibor, all localities in the Chelm district. This finding and the prevalence of clinical cases may suggest that the Chelm district (easternmost area of the Lublin region, bordering Ukraine) is an endemic area of toxoplasmosis. A case of toxoplasmosis in a 39 year old farmer is described in whom reinfection was identified 20 years after primary diagnosis. Rapid increase in specific serologic titres and symptoms typical for toxoplasmosis were noted. The rest of the family and household animals were also found to be positive which supports the suggestion of a family-environmental case of toxoplasmosis. Survey for anti-Toxoplasma antibodies in various domestic and wild animals comprised sera from 262 cows, 120 pigs, 34 geese, 65 chickens, 3 roe deer and 10 sheep from the Lublin region. High percentages of positive results were found in cattle (53.8%) and in pigs (15%). Fowl were positive only in 0-5.9%. The cattle and pigs from the Chelm district are most probably the main sources of toxoplasmosis threatening humans in this area.