Background: Fatty liver disease is defined as the accumulation of fatty acids in the form of triglycerides in the cytoplasm of hepatocytes. Patients with type 2 diabetes mellitus have a risk approximately 3-5 times greater of developing fatty liver disease. Decreased glucose utilization by body cells caused by type 2 diabetes mellitus causes an increase in fat metabolism, which causes the liver to accumulate fat, leading to fatty liver disease. Aim: To determine the relationship between HbA1c values and the duration of type 2 diabetes mellitus diagnosis with the incidence of fatty liver disease at Waled Regional General Hospital, Cirebon. Methods: This study used an observational analytical method with a cross-sectional design. Data were obtained from interviews and medical records. A sample of 33 patients who met the inclusion criteria was obtained using the total sampling technique. The analysis test in this study used Fisher's Exact Test. Results: Most patients had poor HbA1c control (57.6%) and the duration of type 2 diabetes mellitus diagnosis with a range of <5 years (54.5%), and as many as 69.7% of patients did not experience fatty liver disease. The bivariate analysis showed a p-value of 0.707 for HbA1c values and fatty liver disease incidence and a p-value of 0.020 for duration of type 2 diabetes mellitus diagnosis (PR=4.800; 95% CI=1.196-19.266). Conclusion: This study did not find a relationship between HbA1c values and fatty liver disease incidence, but a significant association was found between the duration of type 2 diabetes mellitus diagnosis and fatty liver disease incidence at Waled Regional General Hospital, Cirebon.