It has been shown in many investigations that the abnormally increasing production and deposition of collagen is one of the important mechanisms of pathological scars and other fibrotic diseases [Wang Z, Inokuchi T, Nemoto TK, Uehara M, Baba TT. Antisense oligonucleotide against collagen-specific molecular chaperone 47-kDa heat shock protein suppresses scar formation in rat wounds. Plast Reconstr Surg 2003 May; 111(6):1980–7; Obayashi K, Akamatsu H, Okano Y, Matsunage K, Masaki H. Exogenous nitric oxide enhances the synthesis of type I collagen and heat shock protein 47 by normal human dermal fibroblasts. J Dermatol Sci 2006 Feb; 41(2): 121–6 [e pub. 2005 Sep 19]; Kakugawa T, Mukae H, Hayashi T, Ishii H, Nakayama S, Sakamoto N, et-al. Expression of HSP47 in usual interstitial pneumonia and nonspecific interstitial pneumonia. Respir Res 2005 Jun;14(6): 57; Razzaque MS, Taguchi T. The possible role of colligin/HSP47, a collagen-binding protein, in the pathogenesis of human and experimental fibrotic diseases. Histol Histopathol 1999 Oct; 14(4): 1199–1212; Sharp PA. RNA interference—2001. Genes Dev 2001 Mar 1; 15(5): 485–90; Ohashi S, Abe H, Takahashi T, Yamamoto Y, Takeuchi M, Arai H, et-al. Advanced glycation end products increase collagen-specific chaperone protein in mouse diabetic nephropathy. J Biol Chem 2004 May 7; 279(19): 19816–23 [epub 2004 Mar 5]]. RNA interference is the process that double-stranded RNA induces the homology-dependent degradation of cognate mRNA mediated by 21–23 nucleotide short interfering RNA (siRNA). In this study, we investigated the effect of HSP47-specific siRNA on the fibroblast cells, and then constructed adenovirus containing siRNA against HSP47 to inhibit the formation of scar in animal model. In this pilot study, HSP47 was targeted by this vector. Our results showed that the HSP47-specific siRNA could inhibit the expression of HSP47 at the level of mRNA and protein. Furthermore, adenovirus-mediated transfer of siRNA against HSP47 could inhibit the expression of type I collagen and the formation of scar tissue in animal model. It is likely that the inhibition of HSP47 by RNA interference (RNAi) could be developed as a powerful approach to prevent the scar formation.