History and Objectives: The prevalence of the toxoplasmosis in Iran is varied. Due to morbidity of toxoplasmosis the distribution of the diseases was investigated in urban as well as rural regions of Kashan in 1993.

Materials and Methods: A descriptive study covering 14 rural and 5 urban health centers including 2080 individuals (Age 2-70) was conducted. In accordance with the population of rural and urban regions random samples were taken. A questionnaire was filled and 5mL venous blood sample was collected from every individuals. In additions of 1/20 and 1/100 the presence of antibody was assessed by IFA. Positive samples for titers of greater than 1/100 were tested further for higher dilution. 1/20 dilution was taken the basis infection and 1/400 titer was significant. Confidence interval for the prevalence of the disease was taken with 95% probability.

Results: Incidence of the toxoplasmosis was 50.8% in studied regions (CI=48.7±53). The prevalence for the urban regions was 47.6% (CI=44.8±50.4) and rural areas was 55.2% (CI=52.0±58.4). Antibody titer for 264 (12.7%) was higher than 1/400. the rate of infection were proportional with the age of the individuals.

Conclusion: This study pointed to the fact that the prevalence of the disease was high in the regions investigated. Therefore urgent attention ought to be paid to the spread of the disease and especially to individuals of higher age. It is suggested that further research should be conducted into the prevalence of the disease and the source of disease transmission and at risk individuals.