Nuclear ubiquitous casein and cyclin-dependent kinases substrate (NUCKS) was reported to function as a potential biomarker in various tumors. Thus, we aimed to explore the expression of NUCKS in endometrial cancer (EC) and its clinical significance using quantitative real-time PCR (qRT-PCR) and immunohistochemistry (IHC). qRT-PCR results showed that NUCKS mRNA expression gradually elevated from normal endometrium to atypical endometrial hyperplasia, and to EC (P < 0.05 between each group). NUCKS overexpression was strongly associated with FIGO stage (P = 0.002), histologic grade (P = 0.029), lympho-vascular space involvement (P = 0.014), lymph node metastasis (P = 0.019), and recurrence (P < 0.001). Cox multivariate analysis revealed that NUCKS overexpression was an independent factor for overall survival and recurrence-free survival (P < 0.001 for both). Multivariate logistic regression suggested that recurrence was independently correlated with NUCKS overexpresion (P = 0.039), FIGO stage (P = 0.002), and lymph node metastasis (P = 0.002). In summary, NUCKS overexpression may function as a potential biomarker for prognosis especially for recurrence in ECs.