OBJECTIVE: Inappropriate left ventricular mass (LVM) and microalbuminuria predict cardiovascular events in hypertension. We attempted to evaluate the relationship between inappropriate LVM and albuminuria in hypertensive patients. PATIENTS AND METHODS: Four hundred and two nondiabetic, untreated patients with primary hypertension were studied. The appropriateness of LVM to cardiac workload was calculated by the ratio of observed LVM to the predicted value using the reference equation. Albuminuria was evaluated by the urinary albumin to creatinine ratio. RESULTS: The deviation of LVM from the predicted value was positively related to albuminuria (P < 0.0001). Multiple regression analysis showed that albuminuria (0.0182), pulse pressure (P < 0.0001) and left ventricular hypertrophy (LVH) (P < 0.0001) were the only independent predictors of observed/predicted LVM. When subjects were divided into subgroups on the basis of the presence/absence of inappropriate LVM, patients with inappropriate LVM showed higher urinary albumin excretion (P < 0.0001), regardless of potential confounding factors, including LVH (analysis of covariance, P = 0.0453), and higher prevalence of microalbuminuria (P = 0.0024) compared to those without it. Analogous results were obtained by looking at the study patients on the basis of the presence of micro- or normoalbuminuria. Indeed, patients with microalbuminuria showed higher prevalence of inappropriate LVH compared to other left ventricular geometries (appropriate LVH and absence of LVH) (P < 0.0001). After adjusting for confounders, microalbuminuria entailed a three- and five-fold greater risk of having appropriate and inappropriate LVH, respectively. CONCLUSIONS: Inappropriate LVM is associated with albuminuria in hypertension. These data strengthen the role of microalbuminuria as an indicator of high cardiovascular risk.