In the present study, serodiagnosis as well as trial for vaccination of Toxocara vitulorum were done. Twelve male New Zealand rabbits were divided into 3 equal groups; Toxocara vitulorum immunized group (A), control positive Toxocara vitulorum infected group (B) and control Freund's adjuvant group (C). Enzyme-linked immunosorbent assay (ELISA), Western Blot and protein fractionation by using Sodium Dodecyl Sulphate Gel Electrophoresis (SDS-PAGE) were done. Concerning ELISA results, Toxocara vitulorum-immunized group showed the first positive mean antibody titre (0.623) at the day 14 post immunization and reached the peak (0.936) at the day 21 p.i. In control infected group, the first positive mean antibody titre (0.496) appeared at the day 21 p.i and reached the peak (0.657) at the day 30 p.i. In control adjuvant group, the first positive mean antibody titre (0.418) appeared at the day 21 post immunization and reached the highest level (0.778) at the day 30 p.i Concerning  results of SDS-PAGE, electrophoretic analysis with silver stain revealed 8 protein bands with molecular weights 240, 135, 40, 33, 28, 24, 22 and 18 kDa, respectively. The analysis of immunoblotting cleared polypeptide bands of molecular weights 43, 40, 33, 24, 22 and 18 kDa in different sequences along the experiment. It is concluded that, protein bands of molecular weights 33, 24 and 18 kDa appeared along the course of immunization and still also post infection. Therefore, they are considered as protective bands that can be used for preparation of a purified vaccine. It is worthy to mention that protein bands of molecular weights 43, 40, 33, 24, 22 and 18 kDa were detected early (early diagnostic bands); while those of molecular weights 60 kDa and 50 kDa were detected at the day 45 p.i (late diagnostic bands). Concerning to the histopathological results, lesions were prominent in liver and lungs of control infected group showing several hepatic milky spots as well as diffuse eosinophilic infiltration in addition to haemorrhagic patches and nodules in lung tissues. The picture in immunized group was greatly reduced appearing more or less normal.