Injection drug use (IDU) is a complicated social and medical issue. Infectious diseases often affect morbidity and mortality in people who inject drugs and can complicate the management of comorbid medical and psychiatric conditions. The major complications of IDU include viral and bacterial infections, namely HIV, hepatitis B virus, hepatitis C virus, and bacteremia/endocarditis. These infections, as well as the other medical and psychiatric conditions associated with IDU, complicate treatment, management, and societal prevention of substance use. There are various resources and recommendations that clinicians should track when treating patients who inject drugs; these patients require a multidisciplinary team to manage their challenging medical care. [ Psychiatr Ann . 2017;47(1):33–37.]