The relationship between various risk factors and lung cancer was evaluated in a case-control study. One hundred and forty-one cancer patients newly cytologically or pathologically diagnosed from May 1990 to July 1991 at Tri-Service General Hospital (TSGH) were recruited as cases. Two control groups were also studied: 282 hospital controls two-to-one matched with cases on sex, age, hospital of admission and insurance status were selected from the TSGH Ophthalmologic Department, and 282 neighborhood controls two-to-one matched on sex, age, and residence were randomly selected from eligible neighbors. A comparison of interview data between cases and hospital controls based on multiple conditional logistic regression revealed that cigarette smoking, keeping doves as pet, occupational exposure to cotton dust and working as a cook were risk factors for lung cancer. An inverse association between incense burning and lung cancer was noted. The comparison between cases and neighborhood controls showed lung cancer was significantly associated with cigarette smoking, keeping doves, prior chronic bronchitis, occupational exposure to cotton dust, asbestos and radiation, low frequency of burning incense, and low intake of vitamin A derived from vegetables and fruits. There was no association between lung cancer and working as a cook when cases were compared with neighborhood controls.