The occurrence of helminthiases in Estonia was under extensive observation from 1956 until 1989. Enterobiasis had remained the most prevalent helminthiasis in Estonia in the 1990s. After 1990, the number of helminthological studies decreased. This study was conducted to investigate the occurrence and possible risk factors of enterobiasis among nursery school children in Southeast Estonia. A total of 954 nursery school children were examined from 22 nursery schools in Tartu and Põlva counties in Estonia. Enterobius vermicularis infection was detected using the anal swab technique. The parents of tested children were asked to complete questionnaires so as to ascertain the potential risk factors in children's homes and in their families. The overall rate of being positive for E. vermicularis egg was 24.4%. The occurrence of enterobiasis among the examined nursery schools ranged from 11.8 to 46.2% and from 0 to 61.1% in nursery school groups. All nursery schools were infected. Children 5-8 years of age showed a significantly higher rate of being positive for E. vermicularis egg than the younger children. The overall infection rate was higher among boys and among children from larger families. The infection rate was related to washing of hands after closet use. The socioeconomic status of the family was not associated with the frequency of enterobiasis.