The authors studied a health promotion program called PM-Prep (Peer-Mentored Prep), which was designed to improve disaster preparedness among adults living independently in the community. PM-Prep consists of four 2-hour classes co-taught by a health educator and peer-mentors. Adults were randomly assigned to an experimental arm or a wait-list control arm. Earthquake safety knowledge and preparedness supplies were assessed prior to the intervention and at 1 month after the intervention (N = 82). Adults in the experimental arm significantly increased preparedness by 19 percentage points, from 56% to 75% completed (p ≤ .0001), and improved their knowledge by 8 percentage points, from 79% to 87% correct (p < .001). This is the first peer-mentored, targeted, and tailored disaster preparedness program tested with this population. © AAIDD.