Objective To compare the clinical and pathological differences between IgM nephropathy (IgMN) and IgA nephropathy (IgAN) in children. Methods Clinical manifestations, laboratory examination results, and renal patholog-ical data from 38 children with IgMN and 40 children with IgAN were compared. Results The mean age of onset in IgMN group was younger than that in IgAN group (P<0.05), the mean course before renal biopsy of IgMN group was longer than that of IgAN group (P<0.05), but the incidence of gross hematuria, the level of urinary IgG and albumin, and the incidence of severe glomerular injury were all higher in IgAN group than those in IgMN group (P<0.05). In IgMN group, the level of serum albumin was lower and the urine albumin was higher in the cases with severe glomerular injury than those in the cases without severe glomerular injury (P<0.05);there were more males in those cases with sever glomerular injuries;the incidences of gross hematuria, the level of urine albumin and NAG, and the abnormal basement membrane thickness was higher in the cases with severe tubular injury than those in the cases without severe tubular injury (P<0.05). However, the incidence of severe glomerular injury had no signiifcant difference between the cases with severe and without severe renal tubular injury (P>0.05). In IgAN group, the incidence of proteinuria, RBC casts in tubular, C3 and ifbrinogen deposition, and foot process effacement were higher in the cases with severe glomerular injury than those in the cases without severe glomerular injury (P<0.05); the degree of impairment of renal function, the incidence of severe mesangial cell proliferation, and glomerular sclerosis were more serious in the cases with severe tubular injury than those in the cases without severe tubular injury (P<0.05). Conclusions The clinical and pathological features are different between IgMN and IgAN in children. The renal damage is less in IgMN than that in IgAN children. Different from IgAN children, there is no parallel relationship between tubular and glomerular injury in IgMN children.