AIMS: We aimed to compare levels of urinary albumin excretion and the prevalence of microalbuminuria in UK South Asians and Europeans. Microalbuminuria predicts cardiovascular disease in European origin populations, but evidence from the general population of South Asians is lacking. Coronary heart disease (CHD) mortality is 40-50% higher in UK South Asians compared with the whole population, for reasons that are incompletely understood. METHODS: Microalbuminuria was measured using the albumin-creatinine ratio in an age- and sex-stratified random sample of 1509 adults from European (n = 825), Indian (n = 259), Pakistani (n = 305) and Bangladeshi (n = 120) ethnic groups. RESULTS: Levels of urinary albumin excretion were substantially higher in South Asians (geometric mean albumin creatinine ratio (95% confidence interval) 0.83 (0.75, 0.91)) than in Europeans (0.55 (0.51, 0.60)). Microalbuminuria was associated with older age, hypertension and diabetes, but independently of these risk factors urinary albumin excretion was higher in South Asians than Europeans. CONCLUSIONS: Urinary albumin excretion is higher and microalbuminuria more frequent in UK South Asians compared with the majority ethnic population. Microalbuminuria may be relevant to the causal pathways leading to the excess of cardiovascular mortality and possibly renal failure in UK South Asians.