Introduction: The National Drug Abuse Treatment Clinical Trials Network (CTN) was initiated by the National Institute on Drug Abuse (NIDA) in 2000 with the aim of improving substance use treatment and reducing the time between the discovery of effective treatments and their implementation into clinical practice. While initial trials were conducted almost exclusively in specialty addiction treatment settings, the CTN began evolving strategically in 2010 to conduct research in general medical settings, including healthcare systems, primary care settings, emergency departments, and pharmacies, to broaden impact. The advantages of a research network like the CTN is not only the collective content expertise that investigators contribute to the network, but the collective experience gained by conducting studies in the network and then applying those lessons to future studies., Objective: To summarize trial implementation challenges encountered, and the process by which solutions were identified and implemented, within one of the last early-phase CTN Stage II behavioral intervention studies conducted in a specialty addiction treatment setting., Method and Results: We describe the implementation of the CTN-0037 STimulant Reduction Intervention using Dosed Exercise (STRIDE) trial. Issues encountered during study implementation are categorized into four major areas, described in terms useful to future study teams: 1) study team infrastructure challenges, 2) participant- and site- level challenges, 3) intervention-related challenges, and 4) longitudinal study design challenges. Potential consequences of identified problems and the solutions developed to manage these problems are discussed within the context of these four areas. We propose how to extend these implementation lessons and apply them in other healthcare settings to expand the CTN., Conclusions: Effective study management allows for flexible, collaborative solutions to expected and unexpected obstacles to study success. Implementation strategies derived from the first 15 to 20 years of CTN studies are a result of working with providers and participants, and the ongoing collaboration among CTN investigators and network staff. Timely identification and response to problems during study implementation are critical to the success of a trial, regardless of its design. We believe a collaborative approach to identifying and responding to study implementation challenges will increase the likelihood of successful adoption of relevant, efficacious interventions. As the CTN continues to expand, the wealth of successful trial implementation strategies developed during the first 20 years of the CTN need to be applied and adapted to studies in broader network settings, and considered in conjunction with more formalized implementation science processes that are currently available., Competing Interests: Declaration of competing interest Drs. Shores-Wilson, Walker, Rethorst, Northrup, Silverstein, Horigian, and Stotts have no conflicting interests to declare. Dr. Greer has received research funding from NARSAD and contracted research support from Janssen Research & Development, LLC. She has received consultant fees from H. Lundbeck A/S and Takeda Pharmaceuticals International, Inc. Dr. Warden has owned stock in Pfizer, Inc. and Bristol-Myers Squibb Company within the last five years and has received funding from NARSAD. Dr. Trivedi has served as an adviser or consultant for Abbott Laboratories, Abdi Ibrahim, Akzo (Organon Pharmaceuticals), Alkermes, AstraZeneca, Axon Advisors, Bristol-Myers Squibb, Cephalon, Cerecor, CME Institute of Physicians, Concert Pharmaceuticals, Eli Lilly, Evotec, Fabre Kramer Pharmaceuticals, Forest Pharmaceuticals, GlaxoSmithKline, Janssen Global Services, Janssen Pharmaceutica Products, Johnson & Johnson PRD, Libby, Lundbeck, Meade Johnson, MedAvante, Medtronic, Merck, Mitsubishi Tanabe Pharma Development America, Naurex, Neuronetics, Otsuka Pharmaceuticals, Pamlab, Parke-Davis Pharmaceuticals, Pfizer, PgxHealth, Phoenix Marketing Solutions, Rexahn Pharmaceuticals, Ridge Diagnostics, Roche Products, Sepracor, Shire Development, Sierra, SK Life and Science, Sunovion, Takeda, Tal Medical/Puretech Venture, Targacept, Transcept, VantagePoint, Vivus, and Wyeth-Ayerst Laboratories; he has received grants or research support from the Agency for Healthcare Research and Quality, Cyberonics, NARSAD, NIDA, and NIMH., (Copyright © 2020 Elsevier Inc. All rights reserved.)