Ethiopia has been exhibiting trends that are shifting the populace's way of life toward urbanization. As a result, the country's primary focus is on treating infectious diseases, whereas chronic noncommunicable diseases receive less attention. Type 2 diabetes has emerged as a major noncommunicable disease that is endangering African nations' economic, social, and cultural underpinnings. There has been research mostly on prevalence, factors associated, and glycemic control of diabetes but not adequate on the causes of T2DM in Ethiopia, particularly in the study region. To identify the determinants of type 2 diabetes mellitus among adults at Dill-Chora hospital, from August 30 to October 30, 2021. An unmatched case-control study was carried out at Dill-Chora referral hospital using face-to-face interviews. The data was collected, cleaned, coded, and entered to epi data version 3.1 before being exported to SPSS version 23 for analysis. The analyses used were descriptive and logistic regression. The study included 331 individuals, 113 cases and 218 controls. Cigarette smoking (AOR: 3.15, 95% CI: 1.24-7.96), extra salt consumption (AOR: 5.52, 95% CI: 2.33-13.05), low fruit consumption (AOR: 5.28, 95% CI: 2.12-13.16), infrequent physical activity (AOR: 3.72, 95% CI: 1.65-8.39), waist to hip ratio (AOR: 18.88, 95% CI: 7.35-48.42), and triglyceride level (AOR: 2.93, 95% CI: 1.34-6.32) were strongly linked to the onset of type 2 diabetes mellitus. This study discovered a variety of risk factors for type 2 diabetes, including triglyceride levels, fruit consumption, smoking, increased salt consumption, irregular exercise, and waist to hip ratio. By focusing preventative efforts on these risk factors, the occurrence of type 2 diabetes may be reduced. Furthermore, diabetes mellitus screening is crucial, particularly in those with a high waist-to-hip ratio, a smoking history, and high triglyceride levels.