Objective: This study aimed to evaluate the relationship between sociodemographic characteristics and systemic diseases with oral health in individuals aged 18-65 with the decayed, missing, filled teeth (DMFT) index. Methods: This cross-sectional study included 367 volunteers aged 18-65 years. The sixty seven people who reported that they ate completely sugar-free and received orthodontic treatment were excluded from the study and 300 people (170 female/130 male; average age:38.64±14.19) were evaluated. The patients’ sociodemographic information (age, gender, education, brushing), systemic diseases, medication use and DMFT scores were recorded by the specialist researcher. Data were analyzed by using Kolmogorov Smirnov, Man Whitney-U, Kruskall Wallis test and Post-hoc Tamhane’s T2 test in SPPS software (22.0). Results: The difference in DMFT score with sociodemographic information (age, education, brushing) other than gender was statistically significant (p< .05). DMFT score was found in asthma (12.39±5.17), cardiovascular disease (14.56±7.23) and diabetes (14.00±3.42); was significantly higher compared to healthy (9.39±3.67) people (p< .05). The difference between gastrointestinal disease, thyroid disease, kidney disease and healthy people wasn’t statistically significant (p> .05). However the mean DMFT score in kidney patients (9.00±2.85) was significantly lower compared to asthma, diabetes and cardiovascular disease (p< .05). DMFT score was significantly higher in people using medication (13.77±5.58) than in people not using medication (9.42±3.70)(p< .05). Conclusion: Oral health may be negatively affected by some systemic diseases and drug use. In addition, sociodemographic characteristics have an important effect on oral health. The individual’s sociodemographic characteristics, systemic diseases and medication use should be evaluated in detail in treatment planning and oral health motivation.