This study was aimed to systematically evaluate results of trials examining the effects of omega-3 polyunsaturated fatty acid (n-3 PUFA) consumption on body weight, lean body mass, resting energy expenditure, and overall survival in pancreatic cancer patients. We searched Medline, Pubmed, Embase, and Cochrane databases. We selected randomized controlled trials of n-3 PUFA vs. conventional nutrition in unresectable pancreatic cancer patients. We analyzed our data using the Cochrane statistical package RevMan 5.1. Eleven trials met our inclusion criteria. There was a significant increase in body weight [weighted mean difference (WMD) = 0.62; 95% confidence interval (CI), 0.54-0.69, P < 0.00001) and lean body mass (WMD = 0.96; 95% CI, 0.86-1.06, P < 0.00001), a significant decrease in resting energy expenditure (WMD = -29.74; 95% CI, -55.89-3.59, P = 0.03), and an increase in overall survival (130-259 days vs. 63-130 days) in unresectable pancreatic cancer patients who consumed an oral nutrition supplement enriched with n-3 PUFAs compared to those who consumed conventional nutrition. This preliminary study suggests that n-3 PUFAs are safe and have a positive effect on clinical outcomes and survival in pancreatic cancer patients.