OBJECTIVES: To evaluate whether a pharmaceutical care intervention can result in better understanding about hypertension, an increase in medication adherence to antihypertensive therapy and an improvement of overall health-related quality of life (HRQoL).  METHODS: A randomized control trial was conducted whereby participants received an educational intervention through hospital pharmacists who provided them with information about hypertension treatment and management and the importance of medication adherence. Hypertension knowledge, medication adherence and HRQoL were measured by means of self-administered questionnaires. Descriptive statistics were used to describe the demographic and disease characteristics of the patients. Inferential statistics (Chi square test, Mann-Whitney U test and Wilcoxon signed rank test) were used for inter- and intra-group comparison respectively. SPSS 17 was used for data analysis. RESULTS: Three hundred eighty-five hypertensive patients were randomly assigned to the study [192 in the control group (CG) and 193 in the intervention group (IG)]. No significant differences were observed in either group for mean age, gender, income, locality, education, occupation and duration of disease. There was, however, a significant increase in the participants’ levels of knowledge about hypertension (10.26±1.11, P<0.001) and medication adherence (3.24±0.93, P<0.001) among the IG after the completion of the intervention. Significant association was also reported in the intra-IG group comparison (P<0.001). A significant decrease in overall HRQoL in the IG [(39.69±30.25, P<0.001), inter- and intra-group comparison] was observed after the completion of the intervention programme.  CONCLUSIONS: The pharmacist-led intervention led to a significant increase in the participants’ levels of knowledge about hypertension and a positive impact on medication adherence. Therefore, the role of pharmacists in patient education must be formalized and acknowledged as an official part of the health care system.