Fusobacterium nucleatum is a component of the oral microflora, and in clinical practice it is associated primarily with periodontal diseases. Since 2011, the scientific community has confirmed the association of F. nucleatum with colorectal cancer (CRC) by seeding it from tumor tissue samples. Research has led to the discovery of mechanisms by which this bacterium may contribute to the development, metastasis of CRC and chemoresistance. With the help of its adhesion proteins (FadA and Fap2) F. nucleatum specifically attaches to colorectal carcinoma cells. Following invasion, F. nucleatum induces inflammation, activates β-catenin signaling, and creates a favorable microenvironment for tumor growth and development. Recently, the role of F. nucleatum in other types of oncological pathology, such as oral cavity cancer, head and neck cancer, gastric cancer, esophageal cancer, pancreatic cancer, cervical cancer and breast cancer, has been confirmed. Understanding the mechanisms of association of F. nucleatum with oncological diseases will help to find new approaches in the treatment, prevention and diagnosis of cancer. Thus, further studies of the correlation between F. nucleatum and carcinogenesis are needed, using a multidisciplinary approach and physicians from other specialties.