Hypertension and type-2 diabetes are frequently observed concomitantly in a same patient. There are possibilities to delay the onset of type-2 diabetes, especially in patients already managed for hypertension. Trials on renin-angiotensin blockers show that compared to other drug therapies, there is a lower incidence of diabetes in patients treated by an ACE-inhibitor or an Angiotensin 11 antagonist and the benefit can be estimated at 22% (relative risk at 0.78 with a confidence interval from 0.74 to 0.83). A higher risk of occurrence of type-2 diabetes is particularly noted in those under beta-blocking therapy combined to diuretics. In ALLHAT, the comparison of a thiazide diuretic, an ACE-inhibitor and a calcium antagonist showed that the incidence of new cases of diabetes was the highest in the diuretic group and the lowest in the ACE-inhibitor group. Hypertensive patients under calcium antagonists presented an incidence in between the two other groups. According to a recent hypothesis, the insulin-resistance decrease as a consequence of renin-angiotensin system blocking is related to the recruitment of pre-adipocytes. The NAVIGATOR and ONTARGET trials will probably confirm the preliminary results obtained in this topic. Their results are expected within the 2 next years.