It is rare for one human being to be afflicted with more than one cancer. However with further advances intherapeutic regimens, histopathologic observation, diagnostic modalities and increased curiosity, there are increasing number of case reports of multiple primary cancer. The presents study evaluates 25 histologically confirmed cases of multiple primary cancer from 1974 to 1988 at Kosin Medical Center. The most requent site of the first primary cancer in male was stomach and in female, uterine cervix. The first primary cncer in female occurredin endocrine-related organs(breast, uterus and thyroid) in 63.6 percent. Sychronous cancers are diagnosed simultaneously or within an interval of about six months and synchronous cancers were 16 out of 25 cases. Metachronous cancers are diagnosied at interval of more than six months. There were 9 metachronous cancers and average interval between the first and second primary cancer was 22.8% months. The incidence of multiple primary cancer was 0.11 percent. The average age was 51.9 years at the time of the first primary cancer (53.1 years inmale and 50.3 years in female). CT scan was most helpful in early detection of multiple primary cancersfacilitating biopsy and surgery. Multiple primary cancers are beyond the medical curiosity. Early diagnosis of the disease and careful follow-up study, based on an awareness of the possibility of second cancers, will substantially incresase the survival of these patients.