BACKGROUND: Toxoplasmosis is one of the most prevalent parasitic diseases in human societies and ani- mal populations, particularly pregnant women and domestic animals. This life-threatening infection may cause severe consequences in the fetus. OBJECTIVES: This study was aimed to estimate the prevalence of anti-parasite antibodies in pregnant wom- en and sheep and goat populations of Zabol city, Sistan and Baluchistan Province, Southeast Iran. METHODS: Ninety serum samples of pregnant women and 184 serum samples of sheep and goats were collected and anti-Toxoplasma IgG and IgM antibodies were examined using a commercial enzyme-linked immunosorbent assay kit. Subsequently, the correlation between the seroprevalence of infection and socio-de- mographic data was statistically calculated. RESULTS: Among pregnant women, 13/90 (14%) samples were IgG positive and seroprevalence was signifi- cantly correlated to history of abortion (p <0.05). Among examined sheep and goats, 34 sheep (24.6%) and 3 goats (6.5%) out of 184 (138 sheep and 46 goats) serum samples were positive for parasite-specific IgG. Also, the seroprevalence of infection was significantly associated with animal species (p <0.05), history of abortion (p <0.05) and parity (p <0.05). CONCLUSIONS: According to the findings of this study, despite the relatively low prevalence of infection in pregnant women in Sistan, given the high prevalence of infection in the small ruminant population of the region, more careful monitoring and control of transmission of infection from small ruminants along with other common vectors of the disease are essential. However, more precise investigations are needed to reveal the epidemiological aspects of the parasite in Sistan.