We report on T-subgroup cells in 70 cases of oral-maxillofacial cancer determined by T-monoclone antibody-OKT system. The results are as follows: CD3, CD4/CD8 value of cancer patients was decreased significantly, compared with that of health or oral benign tumor patients. CD8 was significantly increased (P < 0.001); however, CD8 was decreased and CD4/CD8 ratio was increased after operation. 20 cases underwent the dynamic testing, determined in 1 week, 1 and 3 month. The results are as follows: CD3, CD4, CD4/CD8 values were increased gradually and CD8 was decreased gradually in 17 cases of curative patients, but CD4, CD4/CD8, values were decreased and CD8 was increased significantly in 3 cases of metastased patients. Our conclusion is that determination of T-subgroup cells is of reference value for monitoring and treating cancer patients.