This systematic review aimed to analyse: a) the presence and the abundance of Fusobacterium; b) the Fusobacterium species most often found, and c) the most common methods used for their identification in oral/head and neck cancer samples. Design: A protocol was registered on PROSPERO database. This review was conducted following PRISMA guidelines. Literature search was performed on five electronic biomedical databases, namely Pubmed, Scopus, Web of Science, Embase, and Cochrane from their start dates to 30 August 2018. Two reviewers independently assessed the eligibility for inclusion; extracted the data; and evaluated the risk of bias. Results: From 118 unique abstract records, 88 full-text articles were assessed for eligibility. According to inclusion and exclusion criteria, 17 publications were included in this review. Meta-analysis showed an increased prevalence of 6 % (95 % CI, 3–9) of Fusobacterium in tumour lesions than in non-tumour lesions (Fusobacterium prevalence of 16 % in tumour lesions and of 10 % in non-tumour lesions), and a 2.93 higher chance of Fusobacterium being present in tumour lesions (95 % CI, 1.47–5.81). The most common detection methods were based on molecular evidence (64.70 %) (95 % CI, 37.7–84.7). F. nucleatum was the most prevalent species (47.06 %) (95 % CI, 23.5–72). Conclusion: In conclusion, Fusobacterium is present and in higher abundance in oral/head and neck cancer samples when compared to non-cancer samples, suggesting that Fusobacterium may contribute to oral/head and neck cancer development Ver menos