The basement membrane (BM) structure and vascular density (VD) were analysed using collagen IV immunostaining in a series of 88 T1-2MO prostatic adenocarcinomas. The results were correlated with the established prognostic factors and patient survival based on a follow-up of > 11 years. Prostatic cancer cells retained their capacity to synthesize BM components, although defects in the BM structures were associated with T2 category and high Gleason score. Progression of the tumours was related to the defects in BM continuity, and defective BMs were also a sign of poor outcome. High grade tumours were occupied by dense vascular network and dense VD was a sign of a poor outcome. Gleason score was a significant predictor of progression and patient survival, as was the T-category. Multivariate analysis of the prognostic factors indicated that Gleason score included all the available independent prognostic information. The results show that all prostatic adenocarcinomas continue to synthesize BM components, although the structure and continuity is disturbed in poorly differentiated tumours. A rich vascular network is a sign of highly malignant phenotype in prostatic adenocarcinoma. However, an assessment of the BM and VD is of limited independent prognostic value.