The concentration of osteopontin (OPN)in serum of patients with oral squamous cell carcinoma(n=58),benign maxillofacial tumor(n=45)and healthy controls(n=60)was examined using ELISA kit.The OPN level(ng/ml)in the 3 groups was 1 61 .8 ±1 2.6, 52.3 ±8.6 and 48.6 ±1 2.8(P<0.05)respectively,the cases with nodal metastasis and late clinical stage have relatively higher expression levels of OPN(P<0.05).Serum OPN may be related to OSCC progression.