We studied endoglin and vascular endothelial growth factor (VEGF) expression as prognostic markers in prostatic adenocarcinoma in 50 radical prostatectomy specimens. Cases were further categorized by Gleason score as follows: 8 to 10, 9 cases; 7(4 + 3), 9 cases; 7 (3 + 4), 14 cases; 6, 13 cases; and 4 or 5, 5 cases. All cases were immunostained for endoglin, CD31, and VEGF. Positively stained microvessels were counted in densely vascular foci in a x 400 field. VEGF staining intensity was scored on a 2-tiered scale. Results were correlated with survival and other parameters. Endoglin demonstrated significantly more microvessels than did CD31 (mean +/- SD, 37 +/- 15 vs 22 +/- 17; P < .001). VEGF expression was low in 21 cases (42%) and high in 29 (58%). Endoglin correlated positively with Gleason score, lymph node metastases, tumor stage, and preoperative prostate-specific antigen level (P < .05) but not with CD31. VEGF correlated significantly with angiolymphatic invasion and Gleason score (P < .05). A high endoglin microvessel count and VEGF expression correlated with shorter survival. Endoglin is a more specific and sensitive marker for tumor angiogenesis than CD31 and may serve as a prognostic marker for prostatic adenocarcinoma.