Objective：To evaluate the effect of herpes simplex virus thymidine kinase gene and ganciclovir system(HSV-TK/GCV) on humoral and cellular immunological functions in malignant glioma patients.Methods:Twelve patients of malignant glioma were treated with the HSV-TK/GCV system. Peripheral blood and cerebral spinal fluid(CSF) were drawn before, during and afer treatment. Flow cytometry was used to analyze the T lymphocyte subclone of peripheral blood samples. Serum and CSF immunoglobins were quantified through turbidimetry. Results: CD4+T lymphocyte was found elevated during the treatment; NK level fell during the treatment, but rose after treatment. After treatment, cytotoxic lymphocytes(CTL) level was significantly higher than before treatment. Serum IgM and CSF IgG, IgA and IgM levels were seen higher after treatment. Conclusion: HSV-TK/GCV system can stimulate the humoral and cellular immunological functions in malignant glioma patients.