The amount of extraprostatic extension and positive surgical margin correlates in most studies with biochemical recurrence following radical prostatectomy. We studied the influence of focal and diffuse extraprostatic extension and positive surgical margins on biochemical progression using a simple method for quantification. A total of 360 prostates were step-sectioned and totally processed from 175 patients with stage T1c and 185 patients with clinical stage T2 submitted to radical retropubic prostatectomy. Extraprostatic extension was stratified into 2 groups: present up to 1 quadrant and/or section from the bladder neck or apex (Group 1, focal) and in more than 1 quadrant or section (Group 2, diffuse); and, positive surgical margin present up to 2 quadrants and/or sections (Group 1, focal) and in more than 2 quadrants or sections (Group 2, diffuse). The Kaplan-Meier product-limit analysis was used for the time to biochemical recurrence, and an univariate and multivariate Cox stepwise logistic regression model to identify significant predictors. Extraprostatic extension was found in 129/360 (35.8%) patients, 39/129 (30.2%) in Group 1 and 90/129 (69.8%) in Group 2. In univariate analysis but not in multivariate analysis, patients showing diffuse extraprostatic extension (Group 2) had a significant higher risk to develop biochemical recurrence in a shorter time. Positive surgical margin was present in 160/360 (44.4%) patients, 81/160 (50.6%) patients in Group 1 and 79/160 (49.4%) patients in Group 2. Patients with diffuse positive surgical margins (Group 2) had a significant higher risk in both univariate and multivariate analyses. Diffuse positive surgical margin was the strongest predictor on both analyses and an independent predictor on multivariate analysis. Diffuse extraprostatic extension in univariate analysis and positive surgical margins on both univariate and multivariate analyses are significant predictors of shorter time to biochemical progression following radical prostatectomy.38175-84