Interventions to promote evidence-based practices are particularly needed for paraprofessional staff working with minority youth with HIV who have higher rates of HIV infection but lower rates of linkage and retention in care compared to older adults. Utilizing the ORBIT model for behavioral intervention development, we defined and refined a behavioral intervention for providers, Tailored Motivational Interviewing (TMI), to improve provider competence in previous studies (Phase 1a and 1b). The current study focuses on ORBIT Phase 2a-proof of concept. We hypothesized that TMI would be acceptable and feasible and would show a signal of efficacy of improving and maintaining community health worker (CHW) MI competence scores using an innovative statistical method for small N proof-of-concept studies. Longitudinal data were collected from 19 CHWs at 16 youth HIV agencies. CHWs from 8 sites were assigned to the TMI group per the cofunders request. The remaining 8 sites were randomly assigned to TMI or services as usual. MI competence was assessed at baseline and up to 15 times over 2 years. Random coefficient models were utilized to examine time trajectories of competence scores and the impact of the intervention on competence trajectories. Semistructured interviews were conducted to determine barriers and facilitators of TMI. Competence scores in the TMI group significantly increased while the scores of the control group significantly decreased. Further analysis of the intervention group demonstrated that scores significantly increased during the first 3 months after initial workshop and was sustained through the end of the study. Qualitative findings revealed insufficient time and competing priorities as perceived barriers whereas integrating MI into routine agency practices and ongoing training might facilitate implementation. Following a successful proof-of-concept, the next step is a fully randomized pilot study of TMI relative to a control condition in preparation for a stepped-wedge cluster randomized full scale trial. (PsycInfo Database Record (c) 2022 APA, all rights reserved).