OBJECTIVES: To evaluate the level of compliance with antihypertensive medication among Greek hypertensive patients. Furthermore, to investigate the possible association between non-compliance and patient profile as well as specific drug categories. METHODS: A total of 2700 hypertensive patients participated and 2662 were analyzed in the study. The duration of the study was 9 months. Information was collected on different antihypertensive drug categories along with epidemiological data. Morisky scale was used in order to measure compliance. RESULTS: A total of 57.5% of the responders were male (1530 patients) and 1130 were female. Average age of responders was 63 years and average duration of hypertension was 8.6 years. 63.1% of the study population was found to be compliant with their antihypertensive treatment (regardless of the type of antihypertensive treatment the patient was receiving).  From the Morisky scale, 36.2% of patients answered that they sometimes forget to take their medication, 44.9% said that they were sometimes careless when it comes to taking their medicine, 26.9% that when they feel better they forget to take their medicine and 18.4% of the study population answered that when they feel worse, they relate this to their medication and discontinue taking it. The factors found to influence compliance were the level of education, the occupational status and the financial status of the patient as well as the existence of conforming diseases such as duslipidemia and diabetes.   CONCLUSIONS: About four out of ten hypertensive patients fail to comply with their prescribed treatment, increasing the possibility of poor control of their condition. This may be an important obstacle in the assessment of the efficacy of any pharmaceutical therapy and may influence the overall health levels of the patients, since poorly controlled blood pressure may lead to the development of more serious conditions as Congestive Heart Failure and Coronary Heart Disease.