OBJECTIVE To examine the relationship of early life socioeconomic position (SEP) and adulthood periodontitis in the middle aged Korean representative sample. METHODS The 4th Korea National Health and Nutrition Examination Survey data were used. Multivariate logistic regression analyses were conducted on adults aged 30-59 years to estimate the association between parental SEP (education, occupation) and periodontitis and assess the relative impacts of own SEP (education, income and occupation) on periodontitis. Periodontitis (Community Periodontal Index) was dependent variable and parental SEPs were independent variables. RESULTS Own SEP was associated with periodontitis (OR of own education=1.94, OR of own occupation=1.67; OR of the lowest income=1.52). Income was associated with periodontitis after adjustment for own SEPs and parental SEPs simultaneously (adjusted OR of the lowest income=1.68). Parental SEP was associated with periodontitis (OR of father's education=1.66, OR of mother's education=l.64; OR of father's occupation=1.38, OR of mother's occupation=1.44). CONCLUSIONS Early-life socioeconomic disadvantages were significantly associated with adulthood periodontitis in the representative Korean sample (p<0.05). The results also indicated that systematic oral health program and oral education would be needed from early childhood throughout the whole life time to improve periodontal health in adulthood.