We experienced 6 cases of multiple primary cancers associated with lung cancer and report these with a brief review of the literature. During 13 years and 7 months from January 1979 to July 1993, 1312 cases of primary lung can- cer were registered at the Presbyterian Medical Center. Among them, 6 cases were multiple primary cancers compatible with Warren and Gates Criteria. We reviewed the clinical characteristics of theses 6 cases retrospetivly of the basis of medical record. We analyse these 6 cases as below; 1) The incidence of multiple primary cancers associated with lung cancer was 0.46%. 2) Male: female ratio was 5: l. 3) The average time interval between the first and the second cancer was 3.98years. 4) The involved sites were aerodigestive tract in 5 cases and endometrium in 1case. 5) Above 5 cases had heavy smoding history. According to the analysis of our 6 multiple primary cancers associated with lung caner, there seems to be a tendency of developing secondary cancers along the aerodigestive organs which are contiguous with lung. Although we cannot find-out the common etiologic relationship, 5 cases out of 6, has a heavy smoking history. We believe that it is mandatory to have nationwide statistics of mutiple primary cancers associated with lung cancer and to sesrch for the common etioloies, if any.