BACKGROUND: Knee osteoarthritis (KOA) is a chronic disease causing disability in older adults. Self-care is an effective strategy for KOA management in older adults and clinicians have shown increased interest regarding the challenges of self-care activities in these patients.The present study aimed to explore the perception of older adults' patients with KOA regarding barriers and challenges faced in their self-care management.METHODS: In this qualitative study, data were collected using purposeful sampling and in-depth semi-structured interviews with 22 older adults with KOA, their first-degree caregivers, and medical team members in Mashhad, northeast Iran, from April to December 2020. All the interviews were transcribed verbatim. Interviews continued until reaching data saturation. All interviews were recorded.  Data analysis was done using conventional content analysis according to the technique described by Graneheim and Lundman. The MAXQDA (Version 10) was used to organize, code, and manage the data.FINDINGS: Three main themes (confusion, confrontation with increasing stresses, and social rupture) were emerged as the barriers and challenges to self-care among older adults with KOA.CONCLUSION: The results of this study provide a broad range of context-specific of barriers and challenges to self-care among older adults with KOA, which can be used for designing and implementing appropriate interventions to improve self-care in these patients.KEYWORDS: Osteoarthritis, Knee, Aged, Self Care, Qualitative Research