noma at a single institution from 2000 to 2007 were included in this retrospective study. Patients who received neoadjuvant treatment prior to resection and patients with arterial abutment were excluded. Venous involvement was categorized using pre-operative crosssectional imaging as 1) none, 2) portomesenteric vein (PMV) abutment ,180°, 3) PMV abutment ≥180°, and 4) PMV impingement/occlusion. Univariate logistic regression and Cox proportional hazards models were constructed. All four levels of venous involvement were compared to each other; Benjamini-Hochberg method was used to adjust for multiple comparisons. Results: 290 patients (median age 68 years (range 38 90), 58% male) underwent pancreaticoduodenectomy. 30and 90day mortality was 0.7% and 1.7%, respectively. 117 patients (40%) had venous involvement: 73 abutment ,180°, 21 abutment ≥180°, and 23 PMV impingement/occlusion. Margin negative resection was achieved in 83% of patients without venous involvement compared to 73% patients with abutment ,180° (p=0.09), 29% of patients with abutment ≥180° (p,0.01), and 52% of patients with PMV impingement/occlusion (p,0.01). Patients with abutment ,180° were more likely to have margin negative resection than patients with abutment ≥180° (p,0.01). Retroperitoneal margin was positive in 15%, 16%, 48%, and 30% among the patient groups. Patients with abutment ≥180° had more frequent positive retroperitoneal margins than patients without venous involvement or abutment ,180° (both p≤0.01). 58 patients (20%) required PMV resection and reconstruction: 7% of patients without venous involvement compared to 36% with abutment ,180°, 43% with abutment ≥180°, and 48% with PMV impingement/ occlusion (all p,0.01). There were no significant group differences in recurrence-free and overall survival (all p≥0.09). Conclusions: Portomesenteric vein abutment ≥180° is associated with significantly higher risk of margin positive resection. While patients without venous involvement and patients with vein abutment ,180° can be explored for curative resection, patients with PMV abutment ≥180° and impingement/occlusion might benefit from neoadjuvant therapy.