Diabetes Mellitus (DM) is increasingly affecting the productive age group (15–59 years), which should be at the peak of health and activity. Unhealthy lifestyles such as poor diet, obesity, lack of physical activity, and genetic factors are the main risk factors. This study aims to determine the relationship between diet, obesity, genetic factors, and physical activity with the incidence of DM among the productive age group in the working area of Darul Kamal Health Center, Aceh Besar District. This research is a descriptive-analytic study with a case-control design approach. The sample consisted of 160 respondents, including 80 DM patients (cases) and 80 non-DM individuals (controls), using a total sampling technique. Data collection was conducted through interviews using questionnaires, followed by statistical analysis using the chi-square test with SPSS. The Univariate analysis results showed that 39.4% had poor diets, 41.9% were obese, 57.5% had genetic factors, and 53.1% had moderate activity. Bivariate analysis results showed a relationship between diet (P = 0.035; OR = 1.99), obesity (P = 0.037; OR = 1.96), genetic factors (P = 0.000; OR = 3.18), and physical activity (P = 0.000; OR = 3.66) and the incidence of diabetes mellitus among productive-age children in the Darul Kamal Community Health Center, Aceh Besar Regency. The conclusion is that diet, obesity, genetic factors, and physical activity are factors that influence the incidence of diabetes mellitus among productive-age children. It’s recommended that educational programs on the importance of maintaining a good diet and maintaining good health be implemented.