We report two cases of visceral larva migrans (VLM) syndrome by Toxocara in children. The biological presentation was unusual and characterized by persistent secondary thrombocytosis (>1,000 x 10(9)/L) mimicking an essential thrombocythemia and variable hypereosinophilia syndrome. Both children had non-specific symptoms including abdominal pain, skin rash, and fever. The diagnosis was confirmed by serology. The children were treated with either thiabendazole or albendazole, resulting in normalization of eosinophil and platelet counts.