The purpose of this study was to investigate the relationship between oral cancer and such factors as smoking and drinking pattern, oral health status, dietary intake pattern, socio-economic status. Oral cancer patients and other disease patients who visited Yonsei University Dental Hospital from May to September in 2000 were selected as the study subjects. The numbers of cases and controls were 41, 108, respectively. Two groups were matched with age and sex for case control study. Oral examination and questionnaires survey was performed by the dentist. To assess the strength of associations between oral cancer and other variables, chisquare tests were performed. The results were as follows : 1. The durations of smoking and alcohol drinking were not related significantly with oral cancer. But the doses of smoking and alcohol intake increased the risk of oral cancer significantly(OR=2.52, 4.11, p<0.05). 2. Denture wearing, the number of missing teeth and spicy and salty food, coffee, tea and fresh fruit intake frequency did not significantly increase the risk of oral cancer. But low education level, residency in rural area increased risk of oral cancer significantly(p<0.01).