This webinar, presented by Joanne Stekler, MD, MPH, and Vanessa McMahan, MS, PhDc, defined pre-exposure prophylaxis (PrEP) for HIV and summarized the evidence of PrEP’s safety and efficacy for preventing HIV infection, focusing on populations who use substances. It also described research aimed at increasing access and adherence to PrEP among individuals who use methamphetamine in Seattle, Washington.