Background: High blood pressure is an important risk factor for heart disease, stroke and chronic kidney disease. Clear evidence exists that for individuals with high blood pressure (hypertension) lowering blood pressure really reduces this risk. One of the critical factors in the long term control of blood pressure is the regular use of effective antihypertensive medications. In South Africa, poor treatment adherence (attending clinic, re-filling prescriptions, and regularly taking hypertension tablets) is known to be an important and alterable risk factor for uncontrolled high blood pressure and its complications (heart disease, stroke and chronic kidney disease). SMS-text messages have been shown to improve clinic attendance and medication adherence for some diseases (like HIV and TB) in other low-resource settings. It is not clear whether SMS-text messages to support treatment adherence have an effect on long-term blood pressure control. The acceptability, sustainability and scalability such technology also remains to be determined.