As in many other chronic conditions, adherence to prophylactic treatment in migraine is probably poor. In chronic diseases, compliance at one year does not exceed 50%. That could explain the low therapeutic gain seen with migraine preventive medications. It also renders difficult the evaluation of clinical trials on migraine prophylaxis since in most of these trials compliance is not properly assessed. From the patients' perspective, there are several factors that could explain poor adherence to recommended treatments. Essentially, these factors are the expression of the patients'subjective perception of their disease and potential remedies in a context of a positive patient-physician relationship. When migraine prophylactic treatment is considered, patients should be informed of the natural history of their disease and a diagnosis of an accelerated form of migraine should be confirmed. Prophylactic treatment at best would reduce by 50% the frequency of migraine attacks. In most studies, however, the therapeutic gain is in the order of 30-40%. Treatment should be instituted for a minimum time of two to three months and if effective maintained for 6-12 months. The outcome of prophylaxis can rarely be determined in a prospective way. The choice of prophylactic regimens remains empirical, often based on the physician's experience and perception of the mechanism of migraine. A better adherence to prophylactic treatment of migraine could possibly improve outcomes but current methods of improving adherence for chronic health problems are mostly complex and not very effective.