Anal intraepithelial neoplasia (AIN) and 89-100% of anal cancers are caused by persistent infections with high-risk (HR) human papillomaviruses (HPV). In HIV-positive patients, anal HPV infection and AIN are very common and these patients have asignificantly increased risk for anal cancer. However, acontinuous increase in the incidence of anal cancer has also been observed in the general population in recent decades. AIN can clinically present in diverse manners. In HIV-positive patients AIN can be hidden in condylomas. Approximately 3-14% of high-grade AIN progress to anal cancer within 5years. Therefore, screening examinations should be offered to patients with an increased risk for anal cancer. The treatment options for AIN are similar to those for condylomas. HIV-positive patients with controlled immune status and HIV-negative patients with anal cancer respond comparably well to combined radiochemotherapy. AGerman-language S3guideline for anal cancer will be available in 2020. In HIV-positive patients over 26years of age, HPV vaccination showed no effect in acontrolled phase‑3 study. To prevent AIN and anal cancer in the future, HPV vaccination rates need to be increased in HPV-naïve girls and boys.