Drug use is associated with poor linkages to HIV care, reduced retention in care, increased sexual risk behavior, and decreased adherence to medications, leading to inferior clinical outcomes, and increased HIV transmission. HIV-infected people who use drugs (HPWUD) have higher rates of co-occurring psychiatric and medical diagnoses, resulting in increased utilization of services. Many structural and systemic barriers impede the integration of treatment for HIV and substance use (SU). The use of a mobile application combined with an evidence-based training model offers an innovative approach to improving care coordination and linking patients to care in need of dual treatment. A mhealth application delivered via tablet device provides a unique channel to link HIV and SU treatment providers located at off-site clinics. This study will be a Stage I pilot and feasibility study that will be the first to use a theory-based model of care coordination to develop a Care Coordination Intervention (CCI) for treatment providers serving HPWUD. This study seeks to develop a secure mobile technology platform that will: (a) enable rapid communication among providers at multiple clinics, (b) improve linkage to dual care, and (c) improve coordination of patient services. The CCI will also utilize an evidence-based training model to increase provider knowledge in relevant HIV, PrEP, and SU issues. The proposed method of integrating dual care for patients is expected to be an efficient and easily disseminable platform for integrating HIV/SU care that will facilitate communication between providers at multiple clinics and allow for efficient management of patient treatment referrals and service utilization. This project will examine acceptability, feasibility, and sustainability potential using mixed-methods. A three-phase, top-down research approach to adapt, refine, and pilot test the intervention will be conducted. Phase 1 will include individual interviews with key stakeholders and audits of referral and communication processes within each clinic. Phase 2 will include development of the CCI. The investigators will conduct a functionality test and conduct a series of interviews with key stakeholders to inform iterative revision of the CCI. During Phase 3, the investigators will train providers in the CCI and evaluate the feasibility, acceptability, and sustainability potential among HIV and SU treatment providers located at two different clinics via a pre-, post-test design. Data will be gathered at the organizational-, provider-, and patient-levels. Compared to pre-implementation of the CCI in both clinics, the investigators expect that post-implementation data will result in: (H1) greater satisfaction of care coordination at the provider level; (H2) increased frequency and improved quality of interagency communications; (H3) enhanced interagency professional relationships; and (H4) increased dual care retention at the patient level. The long-term goal is to expand the availability of sustainable interventions to improve coordination of HIV and SU treatment services. Data from this research will form the basis of a future multisite R01 proposal for this early career, new investigator applicant.