BACKGROUND: In recent years, lung cancer has been one of most common cause of death in Korea. Despite many physician's high degree of pessimism about the gains made in treatments progressive improvement in the survival of lung cancer by treatment has occurred, particulary in the early stages of the disease. However, a lot of patients refuse treatment or give up in the fight against the disease. This study was done to evaluate factors ifluencing the compliance to therapy and to lead in the establishment of special programs to enhance compliance in patients with lung cancer. METHODS: The medical records of 903 patients, whose ECOG(Eastern Cooperative Oncology Group) performance status was 3 or less and whose medical record was relatively satisfactory, among 1141 patients diagnosed with lung cancer between January 1989 and December 1996 were reviewed retrospectively. Compliance was classified into three groups based on the degree of compliance with physicians practice guideline : (a) complaints ; (b) patients who initially complied but gave up of themselves midway during the course of treatment ; (c) noncompliants who refused the treatment. RESULTS: The overall compliance rats was 63.9%, which was progressively increased from 57.3-61.3% in 1989 and 1990 to 64.2-67.5% in 1995 and 1996. Age, education level and occupation of patients bore statistically significant relationship with the compliance but sell marital status and smoking history did not. The compliance was significantly higher in patients without symptoms than with, and was also significantly higher in patients with good performance status. The compliance was significantly high in patients with NSCLC(non-small cell lung cancer) compared to SCLC(small cell lung cancer), but after exclusion of stage l and ll, among NSCLC, which had higher compliance to surgery there was no significant difference of compliance by histology. The compliance was significantly lower in advanced stage. CONCLUSION: To enhance the compliance, special care including education programs about therapy including complicantion and prognosis are necessary, especially for educationally and economically disadvantaged patients.