Introduction: A wide range of chronic and acute diseases begin with asymptomatic microscopic hematuria. Simultaneous presence of microalbuminuria and microscopic hematuria is suggestive of an important kidney disease. The purpose of this study was to determine the prevalence of microalbuminuria in children with asymptomatic microscopic hematuria.Materials and Methods: This cross-sectional study was done on 150 children aged 2-14 years with asymptomatic microscopic hematuria at Nephrology Clinic of Children’s Hospital Medical Center in 2013-2015. All patients had clinical and laboratory tests such as BUN, creatinine, electrolytes, urine albumin/ creatinine ratio, blood pressure, etc. The obtained data were recorded and analyzed with SPSS (ver. 18). All children with anatomical anomalies, hypertension, previous urinary tract surgery, or nephrolithiasis were excluded from the study.Results: The overall prevalence of microalbuminuria was 14.5 % and there was a significant relationship between microalbuminuria and the presence of dysmorphic red blood cells on urine analysis (p-value<0.05). The incidence of RBC cast was 54% (82 patients). Two children had upper-normal levels of blood pressure for age and sex that were followed closely and received special diets and medications. Twenty-nine patients (18.6%) had a positive family history of asymptomatic microscopic hematuria and the father of one of them had IgA nephropathy with ESRD. In children with microalbuminuria that received drugs for 3-28 months (mean, 6.3 months), microalbuminuria decreased significantly.Conclusions: Isolated asymptomatic microscopic hematuria is a benign disease but its association with proteinuria may indicate a serious problem with the risk of progressive renal disease. It is recommended to determine the microalbumin/creatinine ratio in cases with asymptomatic microscopic hematuria. Keywords: Asymptomatic Microscopic Hematuria; Microalbuminuria; Prevalence; Child