BACKGROUND: Patients with lung cancer and their relatives often ask the advice of relative or friends who are doctors on the treatment and prognosis of the disease. Therefore a doctor's opinion may play a role in determining the treatment modality and affect therapeutic compliance of patients. The purpose of this study was to find the opinion of general practitioners on lung cancer treatment. METHOD: A mail survey for general practitioners in Taegu City and Northern Kyungsang Province was performed. Each individual was sent a written questionnaire in which he or she was asked for ten questions about management and prognosis of lung cancer. RESULTS: Two hundred and twenty eight doctors filled in the questionnaire. Of the respondents, 68% had the experience of being asked about lung cancer by their friends or relatives. About 52% replied that it was better to tell the patient of his or her disease. And about 22% considered it better to follow the relatives' opinion. On the question about choosing the treatment modality, following the doctors' plan was most appropriate in 86.9%, showing that most respondents favored actively recommending doctors. Nonsurgical treatment was preferable in patients over 80 years old with resectable lung cancer and with an increase in age, significant increase was observed in respondents recommending nonsurgical treatment. Most respondents said that they would actively recommend or advise following the doctor' plan about radiotherapy and chemotherapy. But a large percent of the respondents had a negative view on the effect of radiotherapy and chemotherapy. CONCLUSION: The opinions of general practitioners on the treatment and prognosis of lung cancer was variable. And they did not prefer active treatment for patients with old age or advanced lung cancer.