Toxocariasis is a helminthozoonosis due to the infestation of humans by roundworms, Toxocara spp. Actual informations indicate it the most common worm infection in many countries, typically connected with rural areas. The authors analyzed the documentation of 84 children with positive serology to this worm. An individual record was made and following data were restricted: anamnesis data, clinical symptoms, epidemiological data, eosinophils number, level of immunoglobulins G and E. The highest Toxocara spp. seropositivity frequency was found in the schoolchildren aged 7-10. The most frequent clinical findings in children infected Toxocara spp. were lymphadenopathy, hepatomegaly, arthralgia and arthritis. 15.5% of seropositive patients presented non-specific symptoms originating from the central nervous system: headaches, sleep and behavioural disorders, and hyperactivity. The mean eosinophilia in the peripheral blood was detected in the youngest children: 4,023 cell/µl, which is 15.55 times more than the limit value. Hyperimmunoglobulinemia E was detected in all age groups, and the youngest children presented a serum concentration of IgE that was 16.47 times higher than the limit value. Conclusions: 1. Toxocara spp. infection is detected in children at every age, but the most specific age group are schoolchildren, representing 38% of positive individuals. 2. The clinical spectrum of toxocariasis reflects various manifestations depending on the internal organs infected by the migrating worms and the intensity of infection. 3. Eosinophilia seems to be a good marker of infection in young children who have a more symptomatic course of the disease. 4. Hyperimmunoglobulinemia IgE can be the important element which distinguishes between current and past Toxocara infection, but its meaning is not connected with the age of infected children