Hypertension is the first and the most common risk factor to diseases such as cardiovascular, stroke, and renal diseases. The aim of this study was to determine the factors relevant to hypertension knowledge, treatment, and control in southern Iran. In this cross-sectional study, conducted in Kohgiluye Boyer-Ahmad province, south of Iran, a total of 1836 hypertension patients were randomly selected to participate voluntarily in the study. Hypertension treatment and its control were defined during study. In addition, knowledge about hypertension was measured by hypertension knowledge level scale (HK-LS). Treatment rates were 75.5 and 37.7 percent for female and male, respectively. Habitat, education, income, family history with hypertension, smoking, and time of diagnosis to the disease were found to be related to the treatment of the disease. Control rates were 30.7 and 31.4 for males and females, respectively. Habitat, education, and time of diagnosis to the disease were related to control. Over 50 percent of patients had average knowledge on hypertension. Considering the low rate of control and knowledge on hypertension among patients, health care providers should reinforce their services to improve appropriate knowledge level among elders and, also, plan comprehensive programs to promote health in order to encourage patients change and reform their life style.