A high presence of periodontal pathogens such as Porphyromonas gingivalis (P. gingivalis) has been found in cancers at different body locations. The imbalance of the oral microbiome (dysbiosis) promotes the chronic inflammatory process that could contribute to carcinogenesis. To assess the P. gingivalis detection in cancer patients. A search for studies on P. gingivalis and neoplasms was conducted from 1974 to 2021 in the following databases: PubMed (MEDLINE), Cochrane Library, Web of Science (WoS), and Scopus. For dichotomous outcomes, the estimates of effects of an intervention were expressed as odds ratios (OR) using MantelHaenszel (M-H) method with 95% confidence intervals. Funnel plot and Egger’s test for publication bias analysis were used. Also, Newcastle-Ottawa (NOS) studies methodological quality assessment scale was employed. Thirteen studies that involved 1732 cancer patients and 3298 controls without cancer were included in this meta-analysis. P. gingivalis detection was 1.81 times more likely in cancer patients (p<0.01) compared to controls. P. gingivalis detection was also more likely in patients with colorectal (OR: 2.00, p=0.02) or pancreatic (OR: 1.32, p=0.02) tumors. In contrast, oral, esophageal, lung, or breast cancers did not show a significant increase of P. gingivalis detection (p>0.05).