Objective:To explore the role of β-catenin in differential diagnosis between mesenteric fibromatosis and other mesenchymal tumors of gastrointestinal tract. Methods:The expressions of β-catenin, vimentin, smooth muscle actin(SMA), desmin, CD117, CD34 and S-100 in mesenteric fibromatosis, gastrointestinal stromal tumor(GIST), leiomyoma, inflammatory myofibroblastic tumor and nonspecific fibrous hyperplasia were studied by immunohistochemical method. Results:All 5 examples of mesenteric fibromatosis displayed strong nuclear β-catenin staining. All other lesions tested(GIST,leiomyoma,inflammatory myofibroblastic tumor and nonspecific fibrous hyperplasia) lacked nuclear labeling for β-catenin. All tumors showed diffuse strong positive for vimentin. The expressions of CD117 and CD34 were mainly seen in GIST. The expressions of SMA and desmin were mainly seen in leiomyoma. S-100 protein slight staining could be found in few mesenteric fibromatosis, GIST and leiomyoma. Conclusion:Nuclear β-catenin staining is specific and responsive to mesenteric fibromatosis. β-catenin could probably serve as a useful diagnostic and differential diagnostic tool of mesenteric fibromatosis.