The purpose of this study was to explore the expression of ATAD2 in ovarian tumor tissue as well as itsrelationship with degree of malignancy. Tumor tissue from 110 cases of ovarian cancer was collected in accordancewith the Declaration of Helsinki for evaluation of ATAD2 expression iimmunohistochemistry, quantitative PCR(qPCR) and Western blotting. The correlation between the ATAD2 expression and and the prognosis of ovariancancer was evaluated by Cox regression model. In addition, HO-8910 and OVCAR-3 cells were transfected withtwo siRNAs targeting ATAD2. Cell viability was evaluated with MTT assay, and cell migration by transwellmigration assay. ATAD2 was shown to be highly expressed in 65.5% (72/110) of ovarian cancer cases, bothat transcriptional and protein levels. Moreover, highly expression was positively correlated with degree ofmalignancy. Knock-down of ATAD2 in HO-8910 and OVCAR-3 cells was found to reduce cell migration. Inaddition, follow-up visits of the patients demonstrated that the 5-year survival rate was lower in patients withhigh expression of ATAD2. Our study suggested that ovarian tumor tissue may have highly expressed ATAD2,which is associated with tumor stage, omentum-metastasis, ascites and CA-125. Increased ATAD2 may playimportant roles in tumor proliferation and migration. ATAD2 could serve in particular as a prognostic markerand a therapeutic target for ovarian cancer.