Annexins are a structurally related family of calcium- and phospholipid-binding proteins that have been implicated in a broad range of molecular and cellular processes. The altered expression of individual annexins has been implicated in tumor development and progression. In this study the expression of annexin A1 and annexin A2 was studied by immunohistochemistry in intestinal-type sinonasal adenocarcinoma using a study set of 57 intestinal-type sinonasal adenocarcinomas represented on an intestinal-type sinonasal adenocarcinoma tissue microarray to assess its potential role in the pathogenesis of these tumors. Our results showed that annexin A1 expression was consistently lost in 52 (91%) intestinal-type sinonasal adenocarcinomas, as compared with the normal epithelium. The expression of annexin A2 was more heterogeneous, and only 19 (33%) cases showed annexin A2 negative expression. Annexin A2 expression was correlated with the histopathological type, being lower in the mucinous type (P = .022). The loss of annexin A2 expression correlated with a reduced survival in univariate analysis (P = .004). However, the impact of annexin A2 expression on patient survival could be an indirect consequence of its association with the histopathological type, since annexin A2 expression was not found to be an independent predictor in multivariate analyses. These results suggest that annexin A1 expression is frequently and commonly lost in intestinal-type sinonasal adenocarcinoma development. Annexin A2 expression is also reduced in intestinal-type sinonasal adenocarcinoma, and this loss of expression is associated to the more aggressive histopathological types.