BACKGROUND: Albuminuria is a common complication of diabetes and a leading cause of end-stage renal disease. We determined the prevalence of and factors associated with albuminuria in an Australian population and examined the association of albuminuria with glucose tolerance. METHODS: The Australian Diabetes, Obesity, and Lifestyle Study included 11,247 adults aged 25 years and older from 42 randomly selected areas of Australia. Microalbuminuria is defined as an albumin-creatinine ratio of 22 to 220 mg/g (2.5 to 25 mg/mmol) in men and 31 to 220 mg/g (3.5 to 25 mg/mmol) in women, and macroalbuminuria is defined as an albumin-creatinine ratio of 220 mg/g or greater (> or =25.0 mg/mmol). RESULTS: Overall, 25.3% of patients with diabetes mellitus (known [KDM] and newly diagnosed [NDM], type 1 and type 2) had evidence of albuminuria (21.0%, microalbuminuria; 4.3%, macroalbuminuria). Prevalence increased with increasing glycemia (normal glucose tolerance [NGT], 5.1%; impaired fasting glucose [IFG], 9.3%; impaired glucose tolerance, 11.0%; NDM, 17.8%; and KDM, 32.6% [type 2 only]). Patients with diabetes (KDM and NDM) and IFG had an increased risk for albuminuria compared with those with NGT independent of age, sex, and other known risk factors for albuminuria. Logistic regression modeling identified age, duration of diabetes, systolic blood pressure, current smoking, body mass index, and glycated hemoglobin level as independent risk factors for albuminuria. CONCLUSION: This Australian population-based study shows that albuminuria is common among patients with established diabetes, is present before the onset of diabetes, and becomes more prevalent with worsening glucose tolerance.