BackgroundIgA nephropathy and MPGN are common glomerulonephritis in the world that progresses slowly andrenal function can even remain unchanged for decades. Clinically, it presents by isolated hematuria,proteinuria. Histologically, IgA nephropathy presents with acute glomerular damage, mesangial cellproliferation, endocapillary leucocyte infiltration, and crescent formations, these lesions can undergoresolution with sclerotic healing. Since 2013, renal biopsy has been done at the First Central Hospitalof Mongolia a few times. However, the confirmative diagnosis of IgA nephropathy and MPGN remainunknown in Mongolia by renal biopsy. Therefore, we intended to test renal biopsy techniques andconfirm its diagnosis by renal biopsy at the Second Central Hospital of Mongolia.MethodsUltrasound guided renal biopsy had been done for four patients by nephrologist at the Departmentof Nephrology of the Second Central Hospital of Mongolia. All four specimens were evaluated assatisfactory which show more than 8 glomerulus under the light microscopy. Each renal cortical tissuewas divided into two tips: one piece for routine H&E stain and special stains, including Masson’strichrome, and PAS stain; another piece for immunofluorescence by frozen section, which werestained with IgG, IgM, IgA and complement component 3 (C3). Each case was screened by threepathologists.Results:The case which shows mesengial widening, mesengial hypercellularity under the light microscopyor mesangial granular deposition of IgA and C3 by immunofluorescence was diagnosed as IgAnephropathy. We obtained crescent formation with glomerular adhesion in most cases. In addition, weobserved secondary MPGN in one case, which is caused by hepatitis C virus infection.Conclusion: Probably, it is a new step for developing pathologic diagnosis for nephrology in Mongolia.We needs further study for improving renal biopsy technique and confirming the diagnosis of IgAnephropathy and MPGN using electron microscopy and pathological report by oxford classification forIgA nephropathy.