The aim of the present study was to investigate the effect of microRNAs (miRNAs) on the expression level of core1β3‑galactosyltransferase‑specific molecular chaperone (COSMC) in immunoglobulin A nephropathy (IgAN). miRNA expression levels were determined in pediatric patients with IgAN (IgAN group), in patients with other renal diseases (control group) and healthy pediatrics (control group). The target miRNAs of COSMC were investigated in the present study. Western blot analysis was performed to examine the effects of miRNAs on COSMC expression levels. In addition, galactose‑deficient IgA1 (Gd‑IgA1) expression levels were detected following the addition of miRNA‑196b. The present results suggested that the expression levels of 205 miRNAs significantly differed between the IgAN and healthy control groups. The present results also suggested that miRNA‑196b and miRNA‑33a‑3p targeted COSMC, and that miRNA‑196b expression in B lymphocytes was significantly higher in the IgAN group compared with the control group (P<0.0001). However, COSMC expression level was significantly downregulated in isolated B lymphocytes transfected with miRNA‑196b mimics, but Gd‑IgA1 expression levels were increased. Therefore, miRNA‑196b may play a role in the formation of Gd‑IgA1 and IgAN pathogenesis via COSMC regulation.