We verified RAD51-AS1 as a target of E2F1 under negative regulation in EOC. We then examined RAD51-AS1 expression in EOC samples using in situ hybridization (ISH). RAD51-AS1 was localized to the nucleus and found to be a critical marker for clinical features that significantly correlated with poor survival in EOC patients. RAD51-AS1 was also an independent prognostic factor for EOC. Overexpression of RAD51-AS1 promoted EOC cell proliferation, while silencing of RAD51-AS1 inhibited EOC cell proliferation, delayed cell cycle progression and promoted apoptosis in vitro and in vivo. RAD51-AS1 may participate in carcinogenesis via regulation of p53 and p53-related genes. Our study highlights the role of RAD51-AS1 as a prognostic marker of EOC. Survival analysis showed that EOC patients with high RAD51-AS1 expression levels had a significantly decreased overall survival (OS) than those with low RAD51-AS1 expression levels.