Nonadherence to medications is common in cardiovascular diseases because of their long duration, the patient age and the complexity of therapy. Its prevalence depends on the population, the types of drugs and the disease under study. Adherence decreases from the initial prescription and it is usually under 80%, a value defined as satisfactory. Adverse outcomes of nonadherence consist of an increase in ambulatory visits and hospitalization and death rates. The causes of nonadherence are multiple and depend on the patient, the type of medication, the healthcare professional, and the health system. Methods adopted to reduce nonadherence include sanitary education, direct patient-doctor-pharmacist interactions and the use of electronic devices of alert. "Deprescribing", a mechanism proposed to reduce unnecessary or redundant medications, may improve the situation of long-term drug use in patients with cardiovascular disease, thus increasing adherence. Recommendations from the guidelines are sometimes confounding and the role of polypill therapy is still controversial.