The aim of this work was to assess cellular immunity using the Multitest CMI and relate its results with lymphocyte counts and lymphocyte subpopulations determined using monoclonal antibodies against CD4 and CD8 and fluorescence microscopy. We studied 51 patients (31 male), 20 infected with HIV, 18 recurring infections, 5 with cancer, 2 with tuberculosis and 6 with miscellaneous diagnoses. According to Multitest results, patients were classified as normal, hypoergic or anergic. Twenty five percent of patients were normal, 65% hypoergic and 10% anergic. Eighty percent of anergic patients were infected with HIV. No differences in total lymphocyte count were observed between the three groups. CD4 lymphocyte count was lower in anergic patients when compared with the other two groups. All patients with CD4 counts below 200 cells/mm3 were anergic. It is concluded that Multitest CMI is useful for the assessment of cellular immunity and complements the determination of lymphocyte subpopulations.