Lymphocyte subsets of peripheral blood in patients with cancers were analyzed through two color analysis using FCM. Leu-2/Leu-3 and Leu-2+15+/Leu-8-3+ were compared during radiotherapy and periods of follow up in cases with uterine cervical ca. and lung ca. They did not show similar tendencies but just a opposite one in some cases. Both of them, on the other hand, did not appear to be related with the prognosis of patients. However, CTL and NK (potent) did show a relevance with it through the period of follow up. They might be indices which allow to predict the clinical course of Patients with cancers. Further study is now in progress.