This study aimed to determine the association between the number of existing teeth (NET) and socioeconomic status (SES), oral health-related behaviours, and metabolic syndrome in Korean adults aged 55&ndash / 79 years. The study included 3255 adults who underwent oral health examinations and answered questionnaires regarding SES, oral health-related behaviours, and metabolic diseases in the Sixth Korea National Health and Nutrition Examination Survey (2013&ndash / 2015). The dependent variable was the binary status based on the median NET in each age group. The independent variables were based on SES, oral health-related behaviours, and the presence of metabolic syndrome. The study findings showed that the factors associated with the NET were sex, household income, education level, region of residence, daily toothbrushing frequency, dental visit within 1 year, smoking, and metabolic syndrome. NET was lower in males (adjusted OR: 0.74), in low household income group (adjusted OR: 0.77), in primary school graduates (adjusted OR: 0.53), in rural residents (adjusted OR: 0.78), and in medicaid beneficiaries (adjusted OR: 0.78). The interventions aimed at preserving existing teeth in elderly population should consider their SES, oral health-related behaviours, and metabolic syndrome and overhauling current oral healthcare system and redefining the roles of oral health professionals.