Gastric adenocarcinoma is a lethal disease with high incidence in Chinese people. The purpose of this study was to evaluate the expression of urocortin (UCN) in normal gastric mucosa and gastric adenocarcinomas. Immunohistochemical analysis of UCN was performed in 112 surgical specimens (21 normal gastric mucosa specimens and 91 gastric adenocarcinoma specimens varying in histologic grade and pathologic stage). Immunostain intensity was scored on a scale ranging from 0 (absence of staining) to 3 (strong staining). The percentage of UCN stained cells was scored on a scale ranging from 0 (<5%) to 4 (75% to 100%). The UCN immunoscore (ranging from 0 to 12) was the product of the above 2 scores. The UCN immunoscore was high in all 9 normal gastric mucosa specimens, significantly lower in poorly differentiated gastric adenocarcinoma than in well and moderately differentiated tumors (P=0.018), and significantly lower in more advanced pathologic stages of gastric adenocarcinomas than in the early stages of these tumors. Moreover, UCN expression was higher in gastric adenocarcinomas with neuroendocrine differentiation than in mucinous adenocarcinomas and signet-ring cell carcinomas. In conclusion, UCN is expressed in most non-neoplastic gastric glandular epithelia. However, UCN expression inversely correlates with higher tumor grade and advanced TNM stage in gastric adenocarcinomas.