Immunohistochemistry was used to examine the type of lymphocytes in muscle taeniosis-cysticercosis in naturally infected pigs. The inflammatory response studied was classified into lesions of grades 1, 3, and 5. In grade 1, with a minimal inflammatory infiltrate consisting of eosinophils and a few mononuclear cells, the immunostaining showed more CD4+ cells than CD8+ cells and IgM cells. In grade 3, when the granulomatous reaction was not yet well developed and the destruction of the parasite began, CD4+ and Ig M+ were the predominant cells, although CD8+ cells showed a notable increase. In grade 5, with a few parasitic structures surrounded by an extensive granulomatous infiltrate, lymphocyte subsets were decreased in number and did not show differences from grade 1 except for IgM+ cells, which remained increased. The organization of an active inflammatory response against the metacestode of Taenia solium in pigs includes the sequential participation of CD4+, CD8+ and IgM+ lymphocytes.