The purpose of this systematic review and meta-analysis was to determine iron metabolism markers in the peritoneal fluid (PF) of women with endometriosis. Search was conducted in electronic databases including PubMed, the Cochrane Library, and Google Scholar, ClinicalTrials.gov, Scopus, Embase. Clinical trials that reported original data concerning the determination of the content of iron metabolism markers in the peritoneal fluid of women of reproductive age with or without endometriosis were included. 16 studies were included for qualitative analysis. We have conducted three meta-analyses: iron and ferritin concentrations in PF were statistically significantly higher in the endometriosis group (p = 0.01 and p = 0.007, respectively); lactoferrin levels in PF were not statistically different between groups (p = 0.2). According to our results, patients with endometriosis tend to have increased levels of such iron metabolism markers as ferritin and iron in the PF. Therefore, levels of these markers may be used in the future as a diagnostic tool. Understanding these roles of iron and iron metabolism markers in the pathogenesis of endometriosis could inform future research, potentially leading to more effective treatments and diagnostics for the disease.