Background: This study investigated the clinical outcomes according to the preoperative nutritional status and to identify factors influencing long-term unrecovered nutritional status. Methods: Data were prospectively collected from 355 patients who underwent PD between 2008 and 2014. Nutritional status was evaluated by Mini Nutrition Assessment (MNA) and patients were classified into group A (malnourished), group B (risk-of-malnutrition), or group C (well-nourished). MNA score, complications, body mass index (BMI), stool elastase level, biochemical parameters, and quality-of-life (QOL) were collected serially for 1 year. Results: Preoperatively, 60 patients were categorized into group A, 224 into group B, and 71 into group C. Overall complication and pancreatic fistula were higher in groups A and B compared with group C (P = 0.003 vs P = 0.004). QOL, biochemical parameters, BMI and stool elastase level were lowest in group A preoperatively. BMI and stool elastase level remained low after surgery in all groups. Advanced age, low BMI, pre-existing diabetes mellitus, jaundice, exocrine insufficiency and adjuvant therapy were factors influencing long-term unrecovered nutritional status. Conclusion: Preoperative malnourished patients suffer from poor clinical outcomes. Therefore, those with risk factors of malnutrition should be monitored and vigorous efforts are needed to improve their nutrition.