BACKGROUND: Clinical practice guidelines encourage primary care providers (PCPs) to recommend nonpharmacologic treatment as first-line therapy for low back pain (LBP). However, the determinants of nonpharmacologic treatment use for LBP in primary care remain unclear, particularly in low-income settings. OBJECTIVE: To pilot a framework-informed interview guide and codebook to explore determinants of nonpharmacologic treatment use in primary care. METHODS: In this qualitative interview study, we enrolled PCPs and community health workers (CHWs) from four primary care clinics at a safety net hospital. A semistructured interview guide informed by the Consolidated Framework for Implementation Research (CFIR) guided inquiry on barriers/facilitators to nonpharmacologic treatments for LBP (eg, acupuncture, chiropractic care, physical therapy). We included questions on whether current CHW roles may address barriers to nonpharmacologic treatment use. Interviews were audio-recorded, transcribed verbatim, and independently coded by four investigators. An a priori codebook composed of CFIR determinants and known CHW roles guided deductive content analysis to identify major themes. RESULTS: Eight individuals (six PCPs, two CHWs; age range: 32-51 years, five female) participated in hour-long interviews. Half had worked at the hospital for ≥15 years and all reported seeing patients with LBP (range: 2-20 patients per week). All participants identified the following CFIR factors as barriers/facilitators: nonpharmacologic treatment characteristics (perceived cost, relative advantage compared to other treatments); outer setting (patient needs/resources, limited connections with community-based nonpharmacologic treatment) and PCP characteristics (attitudes/beliefs about nonpharmacologic treatments). Although participants indicated several CHW roles could be adapted to address barriers (eg, care coordination, resource linking, case management), other roles seemed less feasible (eg, targeted health education) in our health care system. CONCLUSIONS: Preliminary insight on key determinants of nonpharmacologic treatments for LBP should be further examined in large multisite studies. Future studies may also determine whether a CHW-led strategy can improve nonpharmacologic treatment access and clinical outcomes in primary care.