Chronic infections and infestations represent major causes of cancer. Overall, Helicobacter pylori, HPV, HBV, and HCV are estimated to account for 15% of all human cancers. We have estimated that cancers associated with 6 pathogens in Italy account for 31,000 yearly cases, 42.0%of which is attributable to H. pylori, 34.7%to HBV and HCV, 19.8%to HPV, 2.9%to KSHV, and 0.2% to EBV. These figures represent 8.5% of all incident cases of cancer in Italy. The implementation of anti-HBV vaccination programs in countries with high endemicity resulted in a significant impact on the incidence of hepatocellular carcinoma, and the availability of antiviral drugs is a real opportunity to drastically reduce the cases attributable to HCV. Primary prevention of cervical cancer mainly involves HPV vaccination; two vaccines (bivalent and quadrivalent) are available and a new vaccine (9-valent) has recently been approved by the FDA. Secondary prevention is based on screening programs that include Pap smear cytology and/or HPV test. To reduce the burden of HIV-associated cancers, prevention programs include primary prevention of HIV infection, early diagnosis and treatment, restoration of immune function, reduction in the prevalence of associated infections and risk factors, and secondary prevention. To date, anti-HBV and anti-HPV vaccinations, eradication of H. pylori infection, treatment of HCV and HIV carriers with antivirals, and HPV-related cancer screening prove to be the most effective strategies for the prevention of infection-associated cancers.