The aim of this study was to examine the relationship between the prevalence of geohelminth infections in preschool children living in an urban slum area in Sri Lanka and parental education, socioeconomic status, the use of anthelmintics, and beliefs regarding these helminths. Between October 1992 and February 1993, stool samples were collected from preschool children (< or = 60 months of age) in the Mahaiyyawa area, Kandy, Sri Lanka, and examined using direct smears and a concentration technique. Stool samples which were found to be positive for helminth ova were also examined using the modified Kato-Katz technique. A pretested questionnaire was administered to the mothers or principal caretakers of the children from whom stool samples were obtained to assess parental education, socioeconomic status of the family and knowledge, attitudes and practices related to intestinal parasites, particularly geohelminths. Stool samples from 307 children were examined; 81 (26.4%) were positive for geohelminth ova. Roundworm infections predominated, and were seen in 73 of the 81 (90.1%), either alone or together with whipworm and/ or hookworm infections. All infections were of mild to moderate intensity. Questionnaires were administered to the mothers/principal caretakers of 208 children. Mothers/caretakers of 91 children (45%) claimed that the child was on regular anthelmintics. As the educational level of the mother/caretaker improved, the prevalence of geohelminth infections in the children declined (chi-square for linear trend = 8.19, p = 0.004). However, there was no significant correlation between prevalence of infections and paternal educational levels. Prevalence also tended to increase as the socioeconomic class declined (chi-square for linear trend = 4.899, p = 0.026). Another finding of note in this study was the widespread ignorance and misconceptions regarding geohelminth infections among carers.