Opiate-agonist pharmacotherapy utilizing buprenorphine/naloxone is known to decrease illicit opiate use. However, poor medication management and misuse during self-managed opioid substitution therapy (OST) constrains efficacy, while aggrandizing relapse, hospitalizations and mortality. One of the most inescapable challenges confronted by professionals treating opioid dependence (OD) is assuring medications are taken as prescribed. Affording patients and physicians an interactive toolset to effectively monitor and promote adherence during OST represents a major unmet need that this project will address. Utilizing a forward-thinking approach in mobile health (mHealth) solutions, the Contractor will develop a smartphone application (APP), named SubAID, to engage and support patients and caregivers during OST to promote adherent behavior and provide timely assessment of adherence.