One of the cornerstones of the primary prevention of cardiovascular disease has been screening and early antihypertensive drug treatment of patients with high blood pressure (BP). Nevertheless, recent population studies have shown that awareness and management of high BP levels are far from optimal. In this study, we performed a search for publications providing frequencies of hypertension awareness, treatment and control in different populations. In men, the frequencies of awareness, antihypertensive drug treatment and BP control among all hypertensive patients varied between 23% and 93%, 5% and 89% and 5% and 87%, respectively. In women, the frequencies ranged between 28% and 97%, 6% and 97%, and 0% and 97%, respectively. The percentage of aware hypertensives who were under antihypertensive drug treatment varied between 47% and 95% in men and between 50% and 100% in women. The percentage of hypertensives who were under antihypertensive drug treatment varied between 47% and 95% in men and between 50% and 100% in women. The percentage of treated hypertensives achieving an adequate BP control varied between 29% and 95% in men and between 0% and 100% in women. Overall, women had a better awareness, treatment and control status for hypertension than men, and worse in developing countries than in industrialised countries. Hypertension awareness, treatment and control improved with time, together with the proportion of diagnosed hypertensive patients under treatment and the proportion of well controlled among treated hypertensive patients. We conclude that although the 'rule of halves' no longer applies for screening and treatment of hypertension in industrialised countries, it might still be valid for developing countries and for the effectiveness of antihypertensive drug treatment in all countries.