There is increasing evidence that urinary albumin excretion, even when below the accepted threshold values for normal excretion, may have significant impact on future cardiovascular risks. To further define this, a total of 1086 patients, aged 45 years and older from the population-based, longitudinal 'Study of Health in Pomerania' were evaluated. Patients had echocardiographic analysis at baseline and 5-year follow-up, and were grouped into quartiles according to their baseline urinary albumin-to-creatinine ratio. At baseline, left ventricular mass in the first three quartiles was similar; however, the fourth quartile was significantly elevated and further increased over the 5-year follow-up. In the first quartile, the albumin-to-creatinine ratio and left ventricular mass did not significantly change over 5 years. In the second and third quartiles, the left ventricular mass progressively increased and was significantly correlated with the albumin-to-creatinine ratio. In multivariable analysis, this association was independent of other common cardiovascular risk factors and applicable to both genders. Our study found that the urinary albumin-to-creatinine ratio, even below the current threshold for definition of microalbuminuria, is significantly associated with increased left ventricular mass.