Ubiquitin-specific protease 10 (USP10), a novel deubiquitinating enzyme, had been associated with growth of tumor cell. However, the role of USP10 in gastric cancer carcinogenesis had not been elucidated yet. The aim of this study was to investigate the expression level of USP10 in gastric carcinoma (GC) tissues and cell lines, then to evaluate the clinical significance of USP10 in GC patients. USP10, E-cadherin, Ki67 and p53 expressions were detected in 365 GC and 40 non-cancerous mucosa tissues by immunohistochemistry. Western blot for USP10 was performed on additional fresh GC tissues and GC cell lines. The expression level of USP10 in GC tissues was proved lower than that in non-cancerous mucosa tissues (p < 0.05). It was also lower in GC cell lines (AGS, BGC-823 and MKN45 cells) than that in gastric epithelial immortalized cell line (GES-1). Clinicopathological analysis showed that USP10 expression was negatively correlated with gastric wall invasion (p = 0.009), nodal metastasis (p = 0.002), and TNM stage (p = 0.000). In contrast, a positively correlation between the expression of USP10 and E-cadherin was found (p < 0.05), but there was no relationship proved between Ki67, p53 and USP10 (p > 0.05). On the Kaplan-Meier survival curves, we found poor prognosis in GC patients was associated with negative USP10 expression (p < 0.05). Moreover, USP10 expression was an independent prognostic factor for the overall survival in multivariate analysis. Our findings suggested that USP10 was an independent predictor of prognosis of GC patients.