The cross-reactivity of antiparasite IgE antibody responses induced by allergenic antigens obtained from <i>Trichinella spiralis</i> and <i>Trichinella pseudospiralis</i> was determined by the passive cutaneous anaphylaxis (PCA) technique in BCF₁ mice infected with <i>T. spiralis</i>, <i>Trichinella nelsoni, Trichinella nativa</i>, and <i>T. pseudospiralis</i> and in rats infected with <i>T. spiralis</i> and <i>T. pseudospiralis</i>. Our results demonstrate that when the antigen used for the PCA challenge is derived from muscular L1 larvae of <i>T. spiralis</i>, high IgE antibody titres can be detected from sera of animals infected with <i>T. spiralis</i>, <i>T. nelsoni</i>, or <i>T. nativa</i>, but not with T. pseudospiralis, during the entire life cycle of the parasite. However, when homologous antigens are used in the PCA test, we obtained comparable values of IgE titres in rats and mice infected with both <i>T. spiralis</i> and <i>T. pseudospiralis</i> strains. These results suggest the existence of a high degree of immunologic identity between the allergenic antigens of T<i>. spiralis</i>, <i>T. nelsoni</i>, and <i>T. nativa</i> strains, but not <i>T. pseudospiralis</i>.