16081 Background: A positive surgical margin after radical prostatectomy (RP) in organ confined prostate cancer (pT2) is considered a surgical error. The mechanism and significance of capsular violation may be different between open RP and Robotic Assisted Laparoscopic Prostatectomy (RALP). We compared biochemical disease free survival (BDFS) for RALP patients stratified by margin status. Methods: We reviewed an IRB database of consecutive RALP s. We then compared the BDFS outcomes between those patients who suffered a positive margin (PM) and those who did not, focusing on pT2. To permit adequate follow up we excluded RALPs performed during the last year. BDFS was strictly defined as no PSA≥0.2ng/ml. No pt received adjuvant therapy without a biochemical recurrence. For the purposes of analysis, patients with positive nodes were excluded. Results: 322 patients met inclusion criteria. Mean/median follow-up for the entire cohort was 11.1/10.7mo (range 3.0–41.6). Mean age, BMI and PSA were 60, 26.8, and 6.33 respectively. Gleason distribution was 5 (<1%), 6 (22%), 7 (67%), 8 (6%), and 9 (5%). Pathologic distribution was pT2 248 (77.0%), pT3a 48 (14.9%), pT3b 15 (4.7%), and pT4 11 (3.4%). Overall, 7.8% (25/322) experienced biochemical failure (BF) at a mean/median of 4.1/1.5 months (0.2 - 15.3). BDFS rates by across pathologic stage were pT2 94.8% (235/248), pT3a 87.5% (42/48), pT3b 73.3% (11/15), and pT4 80.0% (8/10). Pathologic stage T2 pts with negative margins (NM) had the same rate of BF, as T2 pts with a PM, [4.4% (9/204) v. 4.5% (2/44) p=0.97] at mean/median 13.0/12.4mo. In multiple linear regression analysis, preoperative PSA >10ng/ml was the most predictive variable of biochemical failure even after adjusting for Gleason sum, pathologic stage, and surgical margin status. Conclusions: There may be a different mechanism between a PM in organ confined open RP pts and RALP pts. In our series of RALPs, only one of 44 pts who were pT2 with a PM suffered BF during followup. At a mean of 13.0mo, BDFS for these pts was 95.5%, and was not significantly different than pT2 pts with a NM. A larger series with longer follow-up will determine whether the oncologic significance of a PM in pT2 RALP patients is different from that of open RP patients. No significant financial relationships to disclose.