Hypertension is associated with high mortality and morbidity that will increase if hypertension is left untreated. Treatment adherence is crucial in blood pressure control, and monitoring patient adherence is essential to the successful management of hypertension, since nonadherence is associated with poor prognosis. There are both direct and indirect methods to monitor adherence. Direct methods can be defined as assessment of treatment response or level of drug or its metabolite in blood, urine and body fluids without any intermediate or agent. Indirect methods require several instruments, such as questionnaires, reports, devices, and monitors. Certain methods may be advantageous in specific clinical and research settings. Advances in technology (new tools, devices, laboratory methods), and new approaches to reporting will not only help patients control high blood pressure but decrease hypertension-related mortality and morbidity.