Hypertensive patients with target organ damage are at increased cardiovascular risk, and should be treated most aggressively. The association between urinary albumin excretion and left ventricular hypertrophy (LVH) in prior studies is inconsistent, and has not been described using a single, random spot urine specimen. Therefore, we evaluated the association between the urinary albumin creatinine ratio (ACR) and left ventricular (LV) mass and also tested the hypothesis that a simple random, single-void urine ACR would identify high risk young, hypertensive, African-American men. We measured echocardiographic LV mass and a random spot urinary ACR in 109 untreated, hypertensive, young, inner city, African-American men. The mean age was 41 +/- 6 years and the mean blood pressure (BP) was 157 +/- 19/107 +/- 13 mm Hg. Microalbuminuria (ACR 30 to 300 mg/g) was present in 22% of subjects. The ACR is higher in the men with LVH than in the men without LVH (P < .05). Increased ACR is a predictor of increased LV mass index (P < .003) using multiple linear regression. An ACR >30 mg/g has a sensitivity of 33% and a specificity of 82% for the diagnosis of echocardiographic LVH. In conclusion, elevated random spot ACR is a marker of increased LV mass, independent of BP, in young urban African-American men with hypertension, and may help to determine the aggressiveness of antihypertensive therapy in this high-risk group.