OBJECTIVES: The objective of this paper was to examine the implementation and effectiveness of a community-based intervention for hoarding disorder (HD) using Cognitive Rehabilitation and Exposure/Sorting Therapy (CREST). DESIGN: This was a mixed-method, pre-post quasi-experimental study informed by the Practical, Robust Implementation and Sustainability Model for implementation science. SETTING: Program activities took place in San Diego County, mainly within clients' homes or community, with some activities in-office. PARTICIPANTS: Participants were aged 60 years or older, met eligibility for Medi-Cal or were uninsured, and met criteria for HD. INTERVENTION: A manualized, mobile protocol that incorporated CREST was utilized. MEASUREMENTS: The Clutter Image Rating and Hoarding Rating Scale were used as effectiveness outcomes. An investigator-created staff questionnaire was used to evaluate implementation. RESULTS: Thirty-seven clients were reached and enrolled in treatment and 15 completed treatment during the initial 2 years of the program. There were significant changes in hoarding severity and clutter volume. Based on the initial 2 years of the program, funding was provided for expansion to cover additional San Diego County regions and hire more staff clinicians in year three. CONCLUSION: Preliminary data suggest that the CREST intervention can be successfully implemented in a community setting with positive results for older adults with HD.