Background and Objectives: The ideal duration of neoadjuvant chemotherapy (NACT) in patients with localized pancreatic adenocarcinoma (PDAC) treated with curative intent is unclear. We sought to determine the prognostic significance of both duration of NACT and Carbohydrate Antigen 19-9 (CA19-9) normalization to NACT. Methods:We examined patients with resectable and borderline resectable PDAC treated with NACT and chemoradiation. Patients were compared by NACT duration (2 vs. 4 months) and by CA19-9 normalization after NACT.Results: Among 171 patients, 83 (49%) received 2 months of NACT, and 88 (51%) received 4 months. After NACT completion, 115 (67%) patients had persistently elevated CA19-9, and 56 (33%) had normalized. Of the 125 patients who had successful surgery, 73 (58%) had normalized CA19-9 postoperatively. Duration of NACT was not associated with overall survival (OS) while CA19-9 normalization after NACT (regardless of duration) was associated with improved OS (hazard ratio[HR] 0.56, 95% confidence interval [CI] 0.35-0.89, p = 0.02). Adjuvant chemotherapy was associated with improved OS among patients without CA19-9 normalization after NACT (HR 0.42, CI 0.20-0.86, p = 0.02) but not among those that normalized, independent of duration.