Background <p>Two-thirds of adults in the United States (U.S.) find recreational and medical cannabis use acceptable. Evidence shows that cannabis use is an effective treatment for pain, and as a harm reducing therapeutic for Substance Use Disorder (SUD). In contrast to most SUD treatment models, some models allow illegal substance use as a harm reduction strategy, which is the case for the SUD treatment program examined in this study. Little is known about veterans with SUD and their perspectives on cannabis use to treat pain. This study characterizes veteran perspectives on cannabis use to manage chronic pain, and pain-related anxiety and poor sleep, during treatment for non-cannabis SUD.</p> Methods <p>Thirty-three U.S. military veterans with a diagnosis of chronic pain, who were receiving care from a Veterans Affairs (VA) SUD treatment program were eligible to participate. Patients with polysubstance use could continue to use substances, as long as they committed to a goal of abstaining from the substance that was the primary focus of their SUD treatment. Most patients had a primary diagnosis of alcohol use disorder (70%), followed by opioid use disorder (18%), and stimulant use disorder (12%). Patients with a primary cannabis SUD were excluded. Patients completed a semi-structured interview. Content analysis identified key narrative themes.</p> Results <p>Approximately one-third of patients reported cannabis use during SUD treatment. Motivations for cannabis use were to alleviate pain, pain-related anxiety and poor sleep quality, and viewing cannabis as a harm reducing therapeutic. Approximately half of patients abstained from cannabis due to negative physical and mental effects experienced in the past, fear of returning to use their primary SUD substance, and to avoid the violation of policies or laws prohibiting cannabis use. Some patients who did not use cannabis showed interest in future cannabis use for pain based on recent cannabis science, laymen’s knowledge and curiosity.</p> Conclusions <p>Patients with non-cannabis SUD may choose to use cannabis to alleviate chronic pain, pain-related anxiety and poor sleep quality, and as a harm reducing therapeutic during SUD treatment. VA and other federally employed clinicians, particularly in states where cannabis is legal, should prepare to educate patients on the medical evidence, gaps, policies and laws related to cannabis to help patients make more informed healthcare decisions related to cannabis use.</p>