Angiogenesis is a key process in tumour growth and metastasis, and Factor-VIII microvascular density has been found to influence prognosis among endometrial carcinoma patients. The CD105/endoglin antibody has been reported to preferentially bind to activated endothelial cells in tissues participating in angiogenesis, and we therefore wanted to compare the prognostic significance of CD105/endoglin to that of Factor-VIII. In a population-based endometrial carcinoma study with long (median 11.5 years) and complete patient follow-up, mean intratumour microvascular density (MVD) assessed using CD105/endoglin was investigated and compared with previous data for MVD assessed using Factor-VIII. MVD by CD105/endoglin was significantly correlated with MVD by Factor-VIII (p=0.001). However, tumours within the two groups defined by the upper and lower quartiles for CD105/endoglin-MVD were both significantly more often metastatic (FIGO-stage III/IV, p=0.03), with high tumour cell proliferation by Ki67 (p=0.007) and with reduced survival (p=0.036) as compared with the intermediate groups. In Cox regression analysis, CD105/endoglin-MVD showed independent prognostic influence when analysed together with patient age, FIGO stage, histologic subtype, histologic grade and Factor-VIII-MVD, while the latter lost its prognostic impact when CD105/endoglin was included. In the subgroup with high MVD, there was a tendency towards improved response to radiation therapy. In conclusion, CD105/endoglin-MVD is significantly associated with FIGO stage, tumour proliferation and prognosis in endometrial carcinoma, indicating that this is a better angiogenic marker in these tumours.