We determined the seroprevalence of Toxocara canis infection in 544 children under 10 years randomly selected from urban and rural areas of Hamadan, An enzyme-linked immunosorbent assay was used for detection of antibodies to T. canis excretion - secretion antigens. Using a questionnaire, epidemiological factors associated with infection were examined, including age, sex, residence. Antibodies to T. canis were detected in 29 children (5.3%) and 19 children (3.5%) were categorized as borderline positive; thus together this gave a prevalence of toxocariasis of 8.8%. No significant differences were found in terms of sex, age and residence