BACKGROUND: Chronic low back pain (cLBP) is complex, disabling, and costly to patients and to society. Patients' social circumstances, beliefs, and behaviors interact in a dynamic way with biomedical factors and have the potential to amplify or reduce suffering. It is important to assess the experience of pain via patient-reported outcomes (PROs). The University of Pittsburgh Mechanistic Research Center, entitled, " is part of the National Institutes of Health's Helping to End Addiction Long-term Initiative. LBP conducted a prospective, observational cohort study to identify phenotypes of over 1000 participants with cLBP. This article reports key information from the PROs and selected demographic variables obtained at the in-person LBP study enrollment visit. METHODS: The LBP study participants completed numerous PROs, including the minimum data set assessments of the NIH Research Task Force on back pain and the NIH HEAL Initiative's Common Data Elements. PROs were organized into five conceptual domains: (1) Pain Characteristics and Qualities, (2) Pain-related Psychosocial Factors, (3) General Psychosocial Factors, (4) General Health and Lifestyle Factors, and (5) Social Determinants of Health (SDoH). Patient Acceptance of Symptom Status, which consists of yes/no responses to 10 questions about whether the level of each of the 10 symptoms is satisfactory, was also assessed. RESULTS: PRO measures were collected from 1007 LBP participants with cLBP. The means and standard deviations, or medians and interquartile ranges, and percentages for the PRO variables collected at the in-person enrollment visit are presented for the overall group and stratified by sex at birth (females and males) and by age (< 60 years old and ≥ 60 years old). For the participants overall, and across sex and age groups, pain intensity and interference were moderate on average. Neuropathic pain, assessed via PainDETECT, was present in 18% of the overall sample, and in 22.5% of those younger than 60. On average, fatigue, depressive and anxiety symptoms, memory and concentration, self-efficacy, and positive outlook were within normal limits, as indicated by PROMIS T-scores. However, PROMIS Physical function was below normal, with T-scores in the mild to moderate range of impairment. When participants were asked to rate the acceptability of their symptom status in 10 areas of function, the most frequently reported areas of dissatisfaction were: pain intensity and interference, physical function, sleep, and fatigue. In the area of SDoH, nearly half (44%) of participants reported having been exposed to traumatic experiences. In the overall group, 36% reported difficulty paying for basic needs such as food, medical care, and heating, while 51% of those in the < 60 group reported this level of financial strain. CONCLUSIONS: The LBP cLBP observational cohort exhibited moderate levels of pain intensity, pain interference with life activities, and pain-related disability. Participants reported mild to moderate levels of pain-related psychosocial factors, and general mental health challenges such as depression and anxiety were relatively rare. Many participants reported a history of exposure to traumatic experiences and having current financial challenges. The LBP PRO results provide reference values for a community sample of persons with cLBP.