The morphologic results recorded in 106 consecutive radical prostatectomy specimens from patients with clinical stage B1-B3 (T2a-c) are presented. All specimens had inked margins and were subjected to morphometric work-up using a 3-mm step section technique. In only 39 (37%) was the tumour confined to a single organ (pT2); 67 (63%) were stage pT3; 40 (37.7%) had only capsular penetration; and 27 (25.4%) had seminal vesicle invasion. In 33 (31.1%) the surgical margin was positive. None of those with pathological stage pT2 had a positive margin. Of the 40 patients with pathological stage pT3a+b, 19 (47.5%) had a positive margin. Of the 27 patients with seminal vesicle invasion (pT3c), 14 (51.8%) had a positive margin. Specimens with only unilateral seminal vesicle invasion or none at all had positive surgical margins in only 25% and 24% of cases, in contrast to those with bilateral seminal vesicle invasion, in which the rate for positive margins was 73%. The mean tumour volume was 8.1 cm3 (0.12-50.13 cm3). There were 9 (8.4%) tumours with a volume < 0.5% cm3 while 62 specimens contained > 0.5 cm3 Gleason 4 and Gleason 5 tumours. Our analysis shows a good correlation of the positive margin rate with tumour volume and especially with volume of the high-grade tumor.