Hypertension-related deaths amount to 9.4 million deaths each year. Despite existing medications for treatment, medication non-adherence serves as a barrier to effective treatment. With the rapid adoption of smartphone technologies, previous studies have examined the impact on hypertension of a smartphone application, but the impact of a stand-alone smartphone application on blood pressure has not been tested in a rigorous manner with regards to hypertension control. This prospective, randomized controlled trial that enrolled 411 patients evaluates the impact of the MedISAFE application on blood pressure control and self-reported medication adherence for patients with uncontrolled blood pressure.