Actinomycosis has been known to involve virtually every anatomic site in the body; those infections involving the head and neck will be reviewed. Actinomycosis of the head and neck has many presentations; it may disguise itself as a tumor or present as a draining abscess which has failed to reveal an infectious agent as its etiology. With more recent attention directed toward the detection of anaerobic organisms especially in the cervicofacial region, this diagnosis is being made more frequently. In this review, a discussion of the bacteriology of Actinomyces, including a review of its taxonomy, morphology, growth requirements, and biochemistry, will be presented. Recommendations are made to clinicians and laboratory personnel who handle such specimens in order that they might obtain maximum information. In addition, infections which mimic or accompany actinomycosis will be reviewed. The diagnosis and management of this infection, including the physical exam, X-ray and laboratory tests, and collection and handling of specimens, as well as the surgical and antibiotic therapy will be discussed in depth. The variety of clinical presentations with their differential diagnosis is used to illustrate the complexity of this disease.