People of Southern Germany as well as European and non European asylum applicants were examined for Toxocara-infection by means of an ELISA with excretory/secretory antigen of Toxocara canis-larvae; in default of a reference method the cut off was defined statistically. In the Stuttgart area, the average seroprevalence of healthy blood donors was 4.8%; children aged 1-7 years showed a seroprevalence of 2.1%. However the low percentage in children sera is probably not the effect of a lower risk of infection, but may result from the fact that most of the tested children live in city areas. Non-Europeans and Eastern Europeans showed a significantly higher seroprevalence (13.7% or 17.7% respectively) in comparison to the blood donors from Southern Germany. This indicates a higher risk of infection in these countries. It was possible to determine the different risk factors for a Toxocara canis-infection with some of the test-participants in Southern Germany. Compared to the low-risk-group (seroprevalence 1.9%), the test groups with risk factors showed a significant increase in seroprevalence: dog-owners 5.6%, owners of domestic cattle 9.4%, cat owners 10.9%, farmers 22.6%. In the presence of several risk factors an additive effect on the seroprevalence could be found: In the test group with one risk factor the seroprevalence (9.2%) was lower than in the test groups with two (10.8%) or three risk factors (18.6%). Considering the high prevalences found in this study and the possible dangerous complications of Toxocara canis-infections, medical and hygienic measures seem to be advisable.