The comparative study of the morphology of invasive larvae and mature males and females T. spiralis and T. pseudospiralis at the head end of the parasites has revealed 14 papillae which are located in 3 circles and 2 which are placed bilaterally, 2 amphidae, and a lanceolar stiletto with a spicular cutting edge. There are no differences in the structure of the heads of these two Trichinella species. The larval cuticle is decorated only with cross folds while longitudinal small-sized folds which are arranged in regular rows appeared in mature species. The vulva in females is located at the levels of a fifth of the body from the head, it is slit-like and oval, that in T. pseudospiralis is situated at the cuticular projection. The anus in T. pseudospiralis larvae is as a cross oval slit, that in adult females is as a hemisphere, and in adult males it is coincident with the copulation pore. As for the structure of the pseudobursa, differences are found in the size and shape of copulation processes, in the arrangement of pre- and postanal papillae against the cloaca, in the size of the formed cuticular projections in T. spiralis, in the shape of the cloacal hole. In the unscrewed copulatory bell, it opens transversely in T. spiralis and vertically in T. pseudospiralis.