Abstract: Objective:To compare the therapy effects of chemotherapy and non-chemotherapy groups and to determine the value of chemotherapy for adult diffuse low-grade gliomas. Methods:We reviewed and analyzed 64patients with adult diffuse low-grade glio -mas admitted to the Beijing Tiantan Hospital from May2005to April 2008. Among the patients, 18received 4 to 12cycles of temozolo -mide chemotherapy after operation and radiotherapy, whereas the other46cases only received radiotherapy. The progression- free survival of the two groups was compared. Results:The median progression-free survival of the chemotherapy and the control groups were67. 8 and 51. 3 months, respectively. The results of the comparison implied a significant difference (χ2 =8. 741 , P=0. 003 ). Conclusion: Chemotherapy can improve the progression-free survival of the patients with adult diffuse low-grade gliomas, and thus, can be recommended as its effective therapy.