This study was done to evaluate the spectrum of diagnoses and identify risk factors for significant kidney disease in asymptomatic children with proteinuria and/or microhematuria detected by routine urinalysis. Clinical and laboratory data were obtained by retrospective chart review of 239 patients referred to a tertiary care center. The predominant diagnosis in children with isolated microhematuria was hypercalciuria and with isolated proteinuria, orthostatic proteinuria. When microhematuria and proteinuria were present in combination, kidney disease was the predominant diagnosis. Urinalysis is a valuable tool to identify patients with kidney disease. The combination of microhematuria and proteinuria increases the risk of having significant kidney disease.