Background <p>Pancreatic atrophy can occur after gastric cancer surgery, but the influencing factors and effects of pancreatic atrophy have not been extensively studied. The aim of this study was to investigate the factors of pancreatic atrophy after gastric cancer surgery and to assess the effect of atrophy on BMI and quality of life, in order to promote postoperative management of patients with higher risk factors of pancreatic atrophy.</p> Methods <p>Clinical data pertaining to 142 patients who underwent surgery for gastric cancer were retrospectively collected, and pancreatic volume was determined using abdominal computed tomography data. Influencing factors of pancreatic atrophy were analysed and the relationship of pancreatic atrophy to BMI and quality of life was measured. Correlation analysis using Pearson or Spearman rank correlation and multiple linear regression were used to analyse the risk factors influencing pancreatic atrophy.</p> Results <p>Pancreatic atrophy was significant in patients with gastric cancer 1 year after surgery, regardless of the surgical procedure. T3 and T4 stages, preoperative low levels of high-density lipoprotein cholesterol(HDL-C) and smoking history were influencing factors of pancreatic atrophy. Pancreatic atrophy was associated with reduced BMI and deterioration of quality of life.</p> Conclusions <p>Clinicians need to monitor pancreatic function, BMI and life quality more carefully in gastric cancer patients with T3 and T4 stages, preoperative low levels of HDL-C and smoking history.</p>