Latinxs in the U.S. are disproportionately affected by HIV and more likely to have delayed diagnosis than their non-Latinx peers. We developed and implemented Sólo Se Vive Una Vez (You Only Live Once), the first Spanish-language campaign aimed at improving HIV testing and prevention among Latinx immigrants in Baltimore, Maryland. Sólo Se Vive Una Vez featured a website ( www.solovive.org ) and social marketing campaign promoting free HIV testing through the Baltimore City Health Department (BCHD) clinic and Latinx outreach team. The campaign was not associated with a change in the overall number of Latinxs obtaining HIV testing. However, Latinx HIV testers who reported being exposed to the campaign had significantly higher rates of high-risk sexual behaviors, mean number of sexual partners, and substance use. The campaign was also associated with increased PrEP referrals through the BCHD Latinx outreach team.