Background: First line carboplatin(C)-paclitaxel(P) and Bev has proved to be an active combination after primary debulking surgery and improve overall survival in sub-optimal resected advanced EOC patients (pts). However, the role of Bev in the NA setting has not been well defined yet. Methods: We performed a phase II randomized open label multicentric study in pts with high grade serous or endometrioid EOC, FIGO stage III-IV, ECOG 0-2, considered unresectable in whom NA CT and interval debulking surgery (IDS) were planned. Main exclusion criteria were intestinal occlusion and contraindication for Bev. Pts were randomized to 4 courses of triweekly C AUC 6 and P 175 mg/m2 iv alone or with at least 3 courses of Bev 15 mg/kg i.v. every 3w in experimental arm. The primary endpoint was complete macroscopic response (CMR) rate at IDS. Secondary objectives were safety, surgical feasibility, optimal surgery rate (OSR), RECIST 1.1 and CA-125 GCIG response rate. Sample collection for translational research was taken at diagnosis and IDS. After surgery pts in both arms completed 3 additional cycles of CT and Bev, followed by maintenance Bev up to 15 mo. Results: Sixty-eight out of seventy-one evaluable pts. Clinical pts characteristics were well balanced, median age 60.0 y.o and a 33.8% stage IV. No differences in CMR were found at IDS (2/33 Control and 2/35 Bev). Bev arm was favoured in rate of surgical feasibility (66.7 vs 88.6%, p = 0.029), while no differences were found in OSR (63.6 vs 65.7%, p = 0.858) and in number of pts considered unresectable at time of IDS (2 vs 0). Median time from IDS to restarting Bev was 7.1 w. Median PFS was 20.3 mo in both arms, 20.13 mo in control arm and 20.36 mo in Bev arm, HR: 1.14 (IC 95%, 0.656 - 1.994). There were lower rates of serious adverse events (grade 3-4) in Bev arm (69.7 vs 42.9%, p = 0.026). 8 pts presented AE of special interest in Bev arm (3G2 proteinuria, 1G2/1G3 hypertension, 1G3 entero-vaginal fistulae, 1G3 entero-cutaneous fistulae, 1G3 deep venous thrombosis, 1G2 bleeding, 1G1 surgical dehiscence). Conclusions: NACT with Bevacizumab was feasible and improved the surgical outcomes at IDS in pts initially considered unresectable. Clinical trial information: 2012-003883-31.