We have used immunphistochemical SP method to detect the expression of nm23 gene protein in human thyroid tissues from 86 carcinomas, 20 adenomas and 25 carcinomatous adjecent tissues. The results showed the positive staining rate were 73.3%, 40.0%and 16. 0% respective (Plt; 0. 005). Although the expression of nm23 protein had no association with the cervical lymph node metas-tases,it was significantly concordant with the tumor cell diffierentiation (Plt;0. 01) ,tumer capsule (Plt; 0. 05) and TNM stage (Plt;0.05).In addition, the patient‘s average survival time in nm23-positive cases was longer than that in nm23-negative ones (Plt;0.01).This data suggest that nm23 gene may play an important role in thyroid carcinogenesis and the expression of nm23 protein would be an useful marker in assessing the prognosis of the thyroid carcinomas.