This report summarizes current (as of 2011) public health recommendations and guidelines from multiple agencies of the U.S. Department of Health and Human Services (DHHS) for science-based public health strategies for the prevention of human immunodeficiency virus (HIV) infection, viral hepatitis, sexually transmitted diseases (STDs), and tuberculosis (TB) (referred to collectively as infectious diseases) among persons who use drugs illicitly and their contacts (sex and drug-using partners) in the United States. In addition, the report recommends integrated delivery of the public health strategies and includes a review of recent programmatic efforts to integrate prevention services for persons who use drugs illicitly. Integrated prevention services provide multiple prevention services at a single venue, coordinate referrals, and provide linkage to services delivered at multiple venues to improve access to high-quality and comprehensive prevention services. Such integration can offer providers and programs the opportunity to address multiple infectious diseases and related health conditions (e.g., substance use and mental disorders) at one time or at a single facility, thereby increasing the likelihood that clients will receive needed services (1). Without access to integrated prevention services, persons who use drugs illicitly would need to go to different facilities to access prevention and treatment services for HIV infection, viral hepatitis, STDs, or TB and for substance use or mental disorders. Implementing integrated services is intended to increase access to services, improve the timeliness of service delivery, and increase the effectiveness of efforts to prevent infectious diseases and disorders that share common risk factors, behaviors, and social determinants. The guidance does not review the topic of physical integration of all medical treatment services for such diseases, especially as different regulatory, accreditation, and licensing policies govern the delivery of treatment services for these diseases. However, the guidance emphasizes the importance of treatment for infectious diseases as a major strategy in preventing their further transmission. The guidance also emphasizes treatment of substance use and mental disorders, comorbidities that must be treated effectively to optimize prevention outcomes for infectious diseases.