Background: Obesity is associated with increased risk of developing pancreatic cancer (PaC), but it is unclear whether it influences mortality in patients with PaC. We performed a systematic review and meta-analysis to assess the association between obesity and PaC mortality. Methods: Through a systematic search of major databases and conference proceedings, up to December 2014, we identified observational studies reporting the association between obesity (premorbid body mass index [BMI] ≥ 30 kg/m²) and all-cause mortality in patients with PaC. We estimated summary adjusted hazard ratio (aHR) with 95% confidence intervals (CI), comparing highest BMI category with normal reference category in each study, as well as mortality risk per 1kg/m² increase in BMI, using random effects model; heterogeneity was measured using the inconsistency index (I²). Results: We identified 10 studies (including 3 pooled cohort studies) with 3,349,338 people, of whom 23% were obese. On meta-analysis, compared with PaC patients with normal BMI, obese PaC patients had a 35% higher mortality (aHR, 1.35; 95% CI, 1.19-1.52) with minimal heterogeneity (I²= 35%), after pooling maximally adjusted HRs. Each 1kg/m² increase in BMI above normal was associated with 13% increased mortality (aHR, 1.13; 95% CI, 1.06-1.22) with minimal heterogeneity (I²= 20%). On subgroup analysis, obesity was associated with increased mortality in Western populations (8 studies; adjusted HR, 1.41; 95% CI, 1.28- 1.56) but not in Asia- Pacific populations (2 studies; adjusted HR, 0.98; 95% CI, 0.76- 1.27). Conclusions: Based on meta-analysis, obesity appears to be associated with increased mortality in patients with PaC in the Western but not Asia-Pacific populations. This may be due to differences in PaC pathophysiology and disease behavior in different geographical locations. Targeting obesity-induced metabolic abnormalities may provide novel pathways for PaC therapy.