The incidence of anal cancer is increasing. In the UK, the incidence is estimated at approximately 1.5 per 100,000. Most of this increase is attributed to certain at-risk populations. Persons who are human immunodeficiency virus (HIV)-positive and men who have sex with men (MSM), Organ transplant recipients, women with a history of cervical cancer, human papilloma virus (HPV), or cervical intraepithelial neoplasia (CIN) are known to have a greater risk for anal cancer. This paper will focus on HPV as a risk factor for anal intraepithelial neoplasia (AIN) and discusses the etiology, anatomy, pathogenesis, management of squamous cell carcinoma (SCC) of the anus.