Introduction: The prevalence of type 2 diabetes mellitus (T2D) has increased considerably while the outcome of diabetic management is suboptimal. In order to promote diabetic management, associated factors for adherence to medications, diet, and physical activity (PA) need to be more clearly identified amongst patients with T2D. Methods: This cross-sectional study was conducted on 206 men and 294 women amongst patients with diabetes who were registered in ten special diabetic clinics in Shiraz, Iran from November 2018 to April 2019. Levels of adherence to medication, Mediterranean diet (MD), and physical activity were measured with validated and appropriate questionnaires. Results: Mean age (± SD) was 56.92 ± 0.52 years and 294 (58.8%) were female. Data showed that reduced adherence to medication, MD, and PA increased glycated hemoblobin (HbA1c). Adherence to medication among low, moderate, and high levels was 27.2%, 59.2%, and 13.6%, respectively. Associated factors such as 50-64 years of age, at least 65 years of age, overweight, obese, divorced widow, smoker, and exsmoker had a significant influence on adherence to medication, P = 0.017, P = 0.018, P = 0.008. P = 0.045, P = 0.026, P\0.004, and P = 0.001, respectively. In addition, adherence to MD among low, moderate, and high levels was 5.4%, 77.2%, and 17.4%, respectively. Associated factors such as 50-64 years of age, at least 65 years of age, overweight, obese, and smoker had a significant influence on adherence to MD, P = 0.011, P = 0.046, P = 0.002, P\0.001, and P = 0.032, respectively. Furthermore, adherence to PA among low, moderate, and high levels was 21%, 68.6%, and 10.4%, respectively. Only the non-smoker factor played a significant role in PA adherence, P = 0.010. Conclusion: Levels of adherence to medications, diet, and PA amongst patients with T2D are not within the acceptable range. Recognized associated factors that contribute to adherence might improve diabetes management and allow one to tailor the appropriate message to improve glycemic indices.Enhanced Digital Features To view enhanced digital features for this article go to https://doi.org/10.6084/ m9.figshare.11358593. A. Mirahmadizadeh Key Summary PointsWhy carry out this study?In order to promote diabetic management, the associated factors for adherence to medications, diet, and physical activity (PA) need to be more clearly identified amongst patients with type 2 diabetes (T2D).Although the levels of adherence to medication, diet, and physical activity have been evaluated separately in other studies in patients with T2D, few studies have simultaneously evaluated the adherence to these factors.What was learned from the study?Reduced adherence to medication, Mediterranean diet (MD), and PA increased HbA1c.Adherence to medication among low, moderate, and high levels was 27.2%, 59.2%, and 13.6%, respectively. Associated factors such as 50-64 years of age, at least 65 years of age, overweight, obese, divorced widow, smoker, and exsmoker had a significant influence on adherence to medication...