Background:Several studies were conducted to investigate the prognostic value of pretreatment serum lactate dehydrogenase (LDH) level in pancreatic cancer (PC), but the results were inconsistent. This study aims to comprehensively assess the prognostic value of pretreatment serum LDH level in PC patients by combining the data of the published literatures on this topic.Methods:Embase, PubMed, and Web of Science were completely retrieved until June, 2018. The observational studies focusing on the prognostic value of pretreatment serum LDH level in PC patients were eligible. STATA version 12.0 was used to undertake the statistical analysis.Results:Eighteen studies with a total of 3345 patients were included in this meta-analysis. The meta-analysis was conducted to generate pooled hazard ratios (HRs) and 95% confidence interval (CI) for overall survival (OS). Our analysis results suggested that high serum LDH level predicted worse OS (HR 1.57, 95% CI 1.30–1.90, P < .001) in PC patients. Moreover, for patients with advanced PC, the prognostic relevance of pretreatment serum LDH level not only existed in those receiving palliative chemotherapy (HR 1.72, 95% CI 1.35–2.18, P < .001), but also in those who were precluded from chemotherapy (HR 1.91, 95% CI 1.4219–2.58, P < .001).Conclusion:The meta-analysis results demonstrated that pretreatment serum LDH level is closely associated with OS, and it may be a useful biomarker for assessing the prognosis of PC patients.