Objective: The prognostic role of lactate dehydrogenase (LDH) in urinary system cancer is still controversial. Thus, we conducted a meta-analysis to assess the prognostic significance of LDH for patients with urinary system cancer. Methods: We searched the PubMed, Embase, Springer and CNKI databases for studies published from January 1991 to February 2015 associated with LDH and urinary system cancer. Study quality was assessed using the Newcastle-Ottawa Scale. After careful review, survival data were extracted from eligible studies. We used pooled hazard ratios (HRs) to estimate the effect of LDH on overall survival (OS) and progression-free survival (PFS). Results: 44 studies meeting the criterion were included. High expression of LDH was significantly correlated with poor OS in urologic cancer (pooled HR 1.93, 95% confidence interval (CI) 1.81-2.07; p < 0.001). The pooled HRs showed significant difference in PFS between LDH over expression group with LDH low expression group (Pooled HR 1.95, 95% CI 1.61-2.36; p < 0.001) in urologic cancer. Conclusion: High serum LDH is associated with OS and PFS in patients with urinary system cancer, and it is an effective biomarker of prognosis in patients with urologic cancer.