OBJECTIVES: to verify the association between adherence to the Mediterranean diet (MedDiet), sociodemographic, clinical, and biochemical factors, and hospital readmission in patients with coronary artery disease. METHODS: prospective cohort study in a tertiary hospital. MedDiet adherence was analyzed at admission and at three and six months after discharge using the Mediterranean Diet Adherence Screener. C-reactive protein, total cholesterol, LDL cholesterol, and triglycerides were analyzed at admission and six months after discharge; readmission was assessed at three and six months. Associations were verified using the generalized estimating equation model, with p-values ≤0.05 considered significant. RESULTS: a total of 146 patients participated, mostly men, with a mean age of 66 years. MedDiet adherence increased from 3% to 41% and 47% during follow-up and was associated with age, female gender, complete higher education, economic activity, and previous myocardial revascularization. CONCLUSIONS: MedDiet adherence was associated with sociodemographic and clinical factors.