The object of the paper was to estimate the advantages and disadvantages of two techniques of the leukocyte migration inhibition (LMI) test (in capillary tubes and in agarose) for the in vitro testing of delayed type hypersensitization. The capillary technique was carried out according to Soborg and Bendixen and the agarose technique according to Clausen. The antigen used in both techniques was PPD in a concentration of 10 micrograms/ml. The techniques were performed in parallel in two groups of individuals: 15 healthy controls and 20 patients with chronic hepatitis. It was observed that in the control group sensitization to tuberculin in vitro was detected by the capillary technique in 7 of the 15 subjects (47%) and by the agarose technique in 4 of the 15 subjects (27%). In chronic hepatitis sensitization to PPD was detected, by the capillary method, in 11 of the 20 patients (55%) and by the agarose method, in 9 of the 20 patients (45%). The results were consistent by the two methods in 18 of the 20 patients. In conclusion the LMI test in capillary tubes is preferable to that in agarose being simpler, more rapid, more sensitive and less expensive.