To improve the immunodiagnosis of human toxocaral disease, a sensitive and specific assay using the Western blotting procedure (WB) with excretory-secretory antigens from Toxocara canis larvae (TES) was developed and compared with the standard enzyme-linked immunosorbent assay method (TES-ELISA) using the same antigens. We tested groups of sera from laboratory animals or patients presenting with toxocariasis or other helminthic diseases and a group of sera from people dwelling in an area endemic for toxocariasis who exhibited hypereosinophilia. Statistically, the WB assay correlated well with TES-ELISA, but the former was more specific for banding patterns corresponding to low-molecular-weight fractions, thus avoiding problems of cross-reactivity with sera infected with other helminthic diseases.