Objective To investigate the effect of immune modulation therapy on cardiac function and lymphocyte subsets in aged patients with chronic heart failure(CHF). Methods CHF(NYHA classification: Ⅱ - Ⅳ)patients older than 60 years were randomly divided into two groups: CHF intervention group received regular therapy and thymopetidum(2 mg/day i.m. for 75 days, n = 48), CHF control group received regular therapy(n = 48), 45 healthy individuals older than 60 years served as normal control. Left ventricular ejection faction of(LVEF), inner diameter of left ventricular end-diastole(LVEDD), inner diameter of left ventricular end-systole(LVESD), lymphocyte subsets, plasma high sensitive C-reactive protein(hsCRP), plasma brain natrium peptide(BNP)and 6 minutes walking distance(6MWT)were measured at before therapy, after the ftrst course(15 days)of treatment and after the third course of treatment(75 days). Results(1)Before therapy, the levels of BNP, hsCRP, CD8 T cells, LVEDD and LVESD were significantly higher and the levels of CD3,CD4, CD19 T cells, NK, CD4/CD8 ratio, LVEF and 6MWT were significantly lower in CHF patients compared to compared normal controls(all P ＜ 0.05).These parameters were similar between CHF intervention group and CHF control group.(2)At 15 days, the levels of CD3, CD4, CD19 T cells and NK weie signiftcantly increased(P ＜ 0.05 or P ＜0.01)while the level of CD8, BNP and hsCRP were significantly decreased(P ＜ 0.05 or P ＜ 0.01)in CHF intervention group compared with CHF control group.(3)At 75 days, the levels of CD3, CD4, CD19 T cells, NK,CD4/CD8, LVEF and 6MWT were significantly increased(P ＜ 0.05 or P ＜ 0.01)while the levels of CD8,BNP, hsCRP and Minnesota Living with Heart Failure Questionnaire(MLHFQ)were significantly decreased (P ＜ 0.05 or P ＜ 0.01)in CHF intervention group compared with CHF control group. Conclusion Thymopetidum, an immunemodulating agent, might regulate the quantity and proportion of lymphocyte subsets and improve cardiac function in aged patients with CHF, indicating that immune modulation therapy might be a new treatment strategy for aged CHF patients.