Introduction: SLE is an important cause of Glomerulonephritis(GN) in the adolescents. Occasionally, GN is the only presenting clinical manifestation without other clinical SLE feature in adolescents. we experienced a case of lupus nephritis in a child presenting with asymptomatic hematuria and proteinuria on school urinary screening tests. Case report: An 12-years-old boy with asymptomatic hematuria and proteinuria was admitted for renal biopsy. The hematuria and proteinuria was accidentally detected by school urinary screening tests. There was no past history of any renal disease, or hypertension. At the time of admission , body temperature was 36.8, PR 80, RR 20 and BP 107/60. Physical examination revealed no hepatomegaly and peripheral or facial edema. Her ophthalmologic and neurologic examinations were normal. Mucocutaneous lesion was not seen. Laboratory workup showed the following: Urinalysis showed specific gravity 1.030, protein 1+ , blood 3+, Dysmorphic RBC 70 % and Urine Protein(UP)/Urine Creatinine(UCr) Ratio 0.143 mg/mg Pheripheral blood analysis showed Hb 14.9 g/dl Hct 42.6%, WBC 6890ul. platelet count of 259,000/uL, CRP 0.01mg/dl, BUN 11.9 mg/dl, serum creatinine 0.54 mg/dl, calcium 8.8 mg/dl, phosphorus 5.2 mg/dl, total protein 7.6 mg/dl, serum albumin 4.3 g/dl, serum cholesterol 166 mg/dl (normal range 100~220 mg/dl), high density lipoprotein 54.0 mg/dl (normal range 31.5-96.6 mg/dl), serum C3 126 mg/dl, C4 30.0 mg/dl, CH 50 and ASO 256 IU/ml. ANA, Anti-ds-DNA Ab, ANCA and LE cell were all negative. The kidney ultrasonography showed no anatomical abnormalities. A Percutaneous renal biopsy was performed. On light microscopic examination, normocellular glomeruli was seen. Electron and Immunofluorescence microscopy showed the glomeulus reveals several focal mesangial immune complex deposits. He was diagnosed as lupus nephritis (WHO class I) and follow up the outpatient clinic without specific medication, as there is little probability of progression. But lupus nephritis can progress to a more-severe renal disease, so he has been followed up since diagnosis. Conclusion: Here we report a case of 12-years-old child with lupus nephritis presenting with asymptomatic hematuria and proteinuria.