Objective: To evaluate the efficacy of granulocyte (-macrophage) colony stimulating factor [G(M)-CSF] in the treatment of concomitant chemoradiotherapy-induced oral mucositis in locally advanced head and neck cancer patients. Metheds: Fifteen patients with locally advanced head and neck cancer was received concomitant chemoradiotherapy, while white blood cell count were less than 1.5×10^9/L with grade Ⅲ/Ⅳ oral mucositis, they were subcutaneously given G(M)-CSF at dose of 100-300μg daily for 3-10 days. Results: After administration of G (M)-CSF, all of the patients had an augmantation of white blood cell count more than 5.0×10^9/L. Complete healing of oral mucositis occurred in 1 patient (CR), partial in 8 patients (PR), whereas 6 patients had no change and none was progressive, the objective response rate (CR+PR) was 60%. Conclusions: G(M)-CSF is proved effective for oral mucositis caused by concomitant chemoradiotherapy in locally advanced head and neck cancer patients.