C3 glomerulopathy defi nes a group of diseases characterized with deposition of C3 alone in the glomeruli in the absence of deposition of immunoglobulin or other complement products. These diseases include dense deposit disease, type 1 membranoproliferative glomerulonephritis (MPGN), familial type 3 MPGN, familial C3 glomerulonephritis associated with mutation in complement factor H related protein 5 and idiopathic C3 glomerulonephritis. Recently, dysregulation of the complement system has been accused in the disease pathogenesis. In this manuscript, two pediatric cases of probable C3 glomerulonephritis according to clinical and renal biopsy fi ndings are presented. One of the cases had presented with the nephrotic-nephritic syndrome and the other with macroscopic hematuria, and both had good prognosis.