Albuminuria is a marker of present and future cardiovascular and renal morbidity, and mortality, in adults. Because the roots of these diseases extend back into childhood, assessment of albuminuria has become relevant to child and adolescent clinical care.Normal levels of albumin excretion in children are well below the cut-off for microalbuminuria. In healthy children, albuminuria relates to fasting insulin, but not blood pressure, BMI, lipid levels, fasting glucose, or insulin resistance. In obese children, albuminuria relates to multiple measures of insulin resistance. In children with type 1 diabetes, hemoglobin A1c seems to be the most consistent clinical predictor of microalbuminuria although multiple mechanisms seem to be involved, including genetic polymorphisms. Children with type 2 diabetes and hypertension already exhibit microalbuminuria.When considering the population as a whole, children make ideal subjects in which to study the natural history of albuminuria given their relative lack of multiple morbidities commonly seen in adults. The unfortunate rise in 'adult' diseases in the pediatric age group makes this especially relevant. There is a need for longitudinal studies examining predictors of elevated urinary albumin levels as well as potential treatment strategies.