Adherence to medication is defined as the extent to which patients follow prescribed therapy. Previous research has shown that poor adherence is a significant problem in cardiovascular care, substantially affecting health outcomes. This study investigates and compares adherence to three groups of cardiovascular drugs — antihypertensives, lipid-lowering agents, and antidiabetic drugs in adult patients with known coronary artery disease. The patient cohort included in the study is part of the patients from the University Hospital Centre Zagreb enrolled in the international EUROASPIRE IV and EUROASPIRE V registries, conducted at different time periods (EUROASPIRE IV 2012-2014; EUROASPIRE V 2016-2018). From each registry, 50 patients were analyzed who, at least six months prior, had either experienced acute coronary syndrome or had undergone elective intracoronary stent placement or coronary artery bypass grafting. Demographic data, medication adherence, and questionnaires on quality of life, depression, and anxiety were analyzed. The results showed that adherence to therapy was excellent in both groups, >90%, with significantly higher adherence in the EUROASPIRE V group (99-100%). There were no differences in age, sex, smoking status, or body mass between the groups. Patients in the EUROASPIRE V group had a better quality of life and less depression and anxiety. Adherence in secondary prevention of cardiovascular diseases is good and a prerequisite for favorable outcomes. An analysis of a larger sample of patients is needed for the results to have higher significance.