Natural Killer (NK) cells are a subpopulation of in vivo activated lymphocytes that display spontaneous cytotoxicity against a variety of targets as virus-infeeted, and transformed neoplastic cells, in major histocompatibility-unrestricted fashion. Depression of the NK aetivity in patients with advanced stages of various types of solid neopls,sms appears to be dependent upon the prcgressive growth and metastatic spread of the tumor. There are many reports that different distribution of subpopulations of lymphocytes in neopiastic tissue may influence the prognosis of the patients, In this study, we have performed immunohistochemieal study with Leu-7, MT1, LN2, and antilysozyrne antiserum on the tissue of uterine cervieal dysplasia and cancer to investigate the distribution of the NK cell, T cell, B cell, and macrophage. The results were as follows ; 1. The major subpopulation of lymphocytes infiltrating the lesion of intraepithelial neoplasia and squamous cell carcinama was T cell. 2. The number of infiltrated. lymphocytes was layer in the lesion of keratinzing type than in that of non keratinizing and small cell earcinorna of the uterine cervix. 3. NK cell was more frequently noted in the malignant lesion than the dysplastic lesion.