Hypertensive patients with left ventricular hypertrophy (LVH) have a higher degree of hyper‐insulinaemia than hypertensive patients without LVH. Obese patients with LVH have also been demonstrated to have a very low glucose disappearance rate after an intravenous glucose bolus. No studies have investigated the difference in insulin action and substrate oxidation in hypertensive patients with and without LVH. For this reason 36 subjects were enrolled for our study: (1) healthy control subjects (n=10); (2) hypertensive patients without LVH (n= 12); and (3) hypertensive patients with LVH (n= 14). All subjects underwent an oral glucose tolerance test (OGTT, 75 g of glucose) and a euglycaemic hyperinsulinaemic glucose clamp (insulin infusion rate, 71 pmol(kgmin)^‐1 for 120min). In this latter test indirect calorimetry allowed substrate oxidation determination. Echocardiographic methods allowed LVH assessment. Hypertensive patients with LVH had the lowest insulin‐mediated nonoxidative glucose metabolism compared to hypertensive patients without LVH (P<0.01) and to healthy subjects (P< 0.001). In the whole group of hypertensive patients (n= 26), partial correlations showed left ventricular mass index (LVMI) associated with fasting plasma insulin levels (r= 0.44 P<0.005), insulin‐mediated whole body glucose disposal (r= ‐0.41 P<0.01) and nonoxidative glucose metabolism (r= ‐0.33 P<0.04) independently of age, body weight, systolic blood pressure and plasma catechola‐mines levels. In conclusion, our data provide evidence that LVH in hypertensive patients is associated with a worsening in nonoxidative glucose metabolism.