Abstract: Objective: To investigate the expressions of telomerase activity and mutatioms of p53 gene in sputa from patients with lung carcinomas and to determine whether the detections are of value in the early diagnosis of lung carcinomas.Methods: The expression of telomerase and mutations of p53 gene in sputa RT-PCR-PAGE and PCR-SSCP were employed respectively and the exfolieted cells were examined by standard papanicolaou staining.Results: The expression rate of telomerase activity in sputa from patients with lung was 58.3%and mutations of p53 gene were 43.3%.No telomerase activity and p53 gene mutations were detected in the sputa from patients with benign bronchial-pulmonary diseases.The difference was significant(P<0.05).There were significant differences between the exfolieted cells in sputa from patients with lung carcinomas,the expression of telomerase activity and the mutations of p53 gene(P<0.005-P<0.05).There were no statistical differences (P>0.05) between the mutations of p53 and the expression of telomerase activity with respect to pathological classifications and location of lung carcinomas.There was a positive correlation between the mutations of p53 gene and the expression of telomerase activity(P<0.01).Conclusions: The telomerase activity and the mutations p53 gene in sputa may serve as tumor markers for the early diagnosis of lung carcinomas.The expression rate of telomerase activity and the mutations rate of p53 gene are no statistically irrelevant with the location and pathological classifications of lung carcinomas.p53 gene may regulate the expression of telomerase activity.