Background/Aim: New markers for ovarian cancer are needed. This study aimed to examine the expression of tumour cell p53 and endothelial cell CD31 proteins and correlate them to clinicopathological factors. Patients and Methods: Expression of proteins was immunohistochemically assessed using tissue sections from 585-599 ovarian cancer patients from the Danish MALOVA study. Results: High CD31 expression was found in poorly differentiated tumours (p=0.0006), and high p53 expression was found in poorly differentiated cancers (p<0.0001), high clinical stage (p<0.0001), non-radical surgery (p<0.0001) and high serum CA-125 values (p<0.0001). CD31 expression showed no prognostic survival value, but high hazard ratios were found for patients with high p53 expression (HR=2.313, p<0.0001). An interaction was found between p53 and stage of cancer, suggesting a prognostic impact of p53 in low-stage, but not in advanced-stage cancer. Conclusion: More than 5% of p53 tissue expression may predict shorter survival of ovarian cancer patients and may be useful for predicting the risk of disease progression in low-stage patients following primary surgery. CD31 has no strong prognostic value.