This article aims to perform a meta-analysis to evaluate the diagnostic value of the immunoglobulin G (IgG)4/IgG ratio of plasmacytic infiltration for IgG4-related diseases.Four databases-EMBASE, ISI Web of Knowledge, PubMed, and the Cochrane Library-were systematically searched. Approximately 200 participants from several studies were included in this research. STATA 11.2 software (Stata Corporation, College Station, TX) and Meta-DiSc 1.4 (Unit of Clinical Biostatistics, Ramon y Cajal Hospital, Madrid, Spain) were used to perform the meta-analysis.Nine studies were included in the meta-analysis. The pooled diagnostic odds ratio was 18.94 [95% confidence interval (CI), 2.89-124.30]. The sensitivity was 58.80% (95% CI, 50.90-66.30) and the specificity was 90.20% (95% CI, 81.20-95.80). The positive and negative likelihood ratios were 3.12 (95% CI, 1.07-9.16) and 0.26 (95% CI, 0.09-0.70), respectively. The area under the curve of the summary receiver-operating characteristic was 0.88.To conclude, the IgG4/IgG ratio of plasmacytic infiltration is modestly effective in diagnosing IgG-related disease.