Abstract: The mechanisms of activation and regulation of T-lymphocytes and their cytokines in malaria is complex and poorly understood. This study evaluated the correlation of parasitaemia with the number of platelets and total leukocytes using Mann-Whitney U and Spearman’s correlation coefficient test, identifies and quantifies subpopulations of Th1, Th2, Th17 and Treg cells during the infection by Plasmodium vivax by flow cytometry after lymphocytes isolated from the peripheral blood. There is a negative correlation between the parasitaemia and the number of platelets and depending on the amount of parasites, patients infected with Plasmodium vivax presents a higher level of thrombocytopenia. No correlation between the number of parasites and total leukocytes was observed in these patients and the number of total leukocytes did not differ when compared to healthy controls. The absolute number of Th1 and Treg cells did not differ between the groups. Patients infected with Plasmodium vivax showed increased number of Th2, Th17 and cytotoxic T-cells. The evaluation of proportion of CD4+ and CD8+ T-cells indicated no differences between the groups. The present indicate that infection induced by P. vivax active specific cells which will participate in immunoregulation against this parasite.