OBJECTIVES/GOALS: To understand the current landscape of clinical trials involving the homeless population by examining opioid or alcohol use disorders and the challenges in clinical trial recruitment. METHODS/STUDY POPULATION: Clinicaltrials.gov was searched with the keywords homeless or unhoused. The search was limited to studies conducted in the United States that were recruiting, not yet recruiting, active and not recruiting, completed, and enrolling. The search findings were further characterized and categorized by the definitions that were used for homelessness. Next, the trials were grouped based on the inclusion of alcohol or opioid use: (A) had no relevant mention, (B) included alcohol or opioid use as a secondary or other outcome measure, or (C) alcohol or opioid were the primary focus of the trial. Lastly, patterns and trends were identified for these trials. RESULTS/ANTICIPATED RESULTS: Out of 161 trials, 77 trials that met search criteria were identified then grouped based on how they classified homelessness: McKinney-Vento (n=5, 6%), DHHS (n=4, 5%), HUD (n=2, 3%), HEARTH Act (n=3, 4%), Custom (trials that specified parameters for homelessness, n=12, 16%), Not Specified (trials that provided no parameters for homelessness, n=26, 34%), and Other/Ambiguous (trials that used enrollment in an independent program as parameters or had unclear parameters, n=25, 32%). Of the 77 clinical trials that targeted homeless populations, 65% did not include alcohol use and 100% did not include opioid use in any outcome measure, 22% included alcohol use in a non-primary outcome measure, and 13% included alcohol use as the primary outcome measure of the study. DISCUSSION/SIGNIFICANCE: The number of clinical trials targeting homeless populations has increased over time, yet there is still no universal definition for classifying an individual as homeless. This lack of harmonization poses a challenge when coupled with the findings that there is a lack of clinical trials targeting opioid or alcohol use disorders.