Purpose:To study the expression of telomerase,p53 and p16 genes in non small cell lung cancer(NSCLC). Methods:The expression of telomerase, p53 and p16 genes were examined in 40 NSCLC cases by SP and TRAP methods, respectively. Results:The positive expression rates of telomerase,p53 and p16 genes in NSCLC were 92.5%, 37.5% and 66.7%, respectively. The positive expression rate of p53 gene correlated closely with the T and pathological staging of NSCLC ( P 0.05). Telomerase activity was correlated with the expression rate of p53 gene and pathological stages but negatively correlated with the ages of NSCLC patients( P