Aldehyde dehydrogenase 5 family, member A1 (ALDH5A1) belongs to the superfamily of aldehyde dehydrogenases (ALDHs). However, the prognostic value of ALDH5A1 in ovarian cancer remains unclear. The aim of this study was to explore the relationship between ALDH5A1 and the prognosis of patients with ovarian cancer (OC). We compared the expression of ALDH5A1 in OC to that innormal controls, using GSE40595 profiling data. Tissue microarray analysis was conducted for192 OC patients, 14 adjacent normal ovary tissues, and 2 normal ovary tissues. Using the Kaplan-Meier plotter (KM plotter) database, updated gene expression data and survival information of a total of 1583 OC patients were used to evaluate the prognostic value of ALDH5A1 in OC patients. We found that ALDH5A1 mRNA expression was downregulated in OC patients compared with that innormal tissues. In survival analyses, we found that ALDH5A1 was positively linked to prognosis in patients with OC, particularly in those with serous ovarian cancer (SOC). In addition, high Ctranscription activity of ALDH5A1 was correlated with better overall survival in SOC patients expressing mutatedTP53, but not in those expressing wild-type TP53. In pathological grades II/III, a high mRNA level of ALDH5A1 was associated with improved overall survival. The positive association between ALDH5A1 and prognosis was found not only in early stages(I and II), but also in advanced stages (III and IV) of SOC patients. results indicate that ALDH5A1 is an excellent predictive factor of OC and may play crucial roles in OC progression.