Silent mating type information regulation 2 homolog-1 (SIRT1) is a member of sirtuin family. Its role in endometrial carcinoma (EC) is controversial and unclear. This study aims to define the SIRT1 immunoexpression pattern in endometrial carcinoma (EC), its relationship with clinicopathological features, and its prognostic significance. A tissue microarray was constructed and contained 71 endometrial carcinomas, 28 endometrial hyperplasia, and 30 normal endometrial tissues. An immunostaining study was completed using anti-SIRT rabbit polyclonal antibody. SIRT1 immunoexpression was scored and analysed. Positive immunostaining was found in 29 of the 71 (40.8%) endometrial carcinomas and in 7 of the 58 (12.1%) nonneoplastic endometrial tissues. SIRT1 immunoexpression findings were not related to age, histological type, tumor size, myometrial invasion, lymphovascular invasion, surgical resection margin, lymph node metastasis, FIGO staging, local recurrence or survival. In endometrial carcinoma, SIRT1 immunoexpression is expressed at greater levels in malignant endometrial tissue than in hyperplastic and normal endometrial tissues. However, no relationship was found between SIRT1 expression and other clinicopathological parameters. More studies are needed to explore the role of SIRT1 in ECs.