Intestinal fibrosis is a clinically important issue in Crohn's disease (CD). Heat shock protein (HSP) 47 is a collagen-specific molecular chaperone involved in fibrotic diseases. The molecular mechanisms of HSP47 induction in intestinal fibrosis related to CD, however, remain unclear. Here we investigated the role of interleukin (IL)-17A-induced HSP47 expression in intestinal fibrosis in CD.Expressions of HSP47 and IL-17A in the intestinal tissues of patients with IBD were determined. HSP47 and collagen I expressions were assessed in intestinal subepithelial myofibroblasts (ISEMFs) isolated from patients with IBD and CCD-18Co cells treated with IL-17A. We examined the role of HSP47 in IL-17A-induced collagen I expression by administration of short hairpin RNA (shRNA) to HSP47 and investigated signalling pathways of IL-17A-induced HSP47 expression using specific inhibitors in CCD-18Co cells.Gene expressions of HSP47 and IL-17A were significantly elevated in the intestinal tissues of patients with active CD. Immunohistochemistry revealed HSP47 was expressed in α-smooth muscle actin (α-SMA)-positive cells and the number of HSP47-positive cells was significantly increased in the intestinal tissues of patients with active CD. IL-17A enhanced HSP47 and collagen I expressions in ISEMFs and CCD-18Co cells. Knockdown of HSP47 in these cells resulted in the inhibition of IL-17A-induced collagen I expression, and analysis of IL-17A signalling pathways revealed the involvement of c-Jun N-terminal kinase in IL-17A-induced HSP47 expression.IL-17A-induced HSP47 expression is involved in collagen I expression in ISEMFs, which might contribute to intestinal fibrosis in CD.