OBJECTIVE: To evaluate the effect of Integral-based hatha yoga in sedentary people with arthritis. METHODS: There were 75 sedentary adults aged 18+ years with rheumatoid arthritis (RA) or knee osteoarthritis randomly assigned to 8 weeks of yoga (two 60-min classes and 1 home practice/wk) or waitlist. Poses were modified for individual needs. The primary endpoint was physical health [Medical Outcomes Study Short Form-36 (SF-36) physical component summary (PCS)] adjusted for baseline; exploratory adjusted outcomes included fitness, mood, stress, self-efficacy, SF-36 health-related quality of life (HRQOL), and RA disease activity. In everyone completing yoga, we explored longterm effects at 9 months. RESULTS: Participants were mostly female (96%), white (55%), and college-educated (51%), with a mean (SD) age of 52 years (12 yrs). Average disease duration was 9 years and 49% had RA. At 8 weeks, yoga was associated with significantly higher PCS (6.5, 95% CI 2.0-10.7), walking capacity (125 m, 95% CI 15-235), positive affect (5.2, 95% CI 1.4-8.9), and lower Center for Epidemiologic Studies Depression Scale (-3.0, 95% CI -4.8 - -1.3). Significant improvements (p < 0.05) were evident in SF-36 role physical, pain, general health, vitality, and mental health scales. Balance, grip strength, and flexibility were similar between groups. Twenty-two out of 28 in the waitlist group completed yoga. Among all yoga participants, significant (p < 0.05) improvements were observed in mean PCS, flexibility, 6-min walk, and all psychological and most HRQOL domains at 8 weeks with most still evident 9 months later. Of 7 adverse events, none were associated with yoga. CONCLUSION: Preliminary evidence suggests yoga may help sedentary individuals with arthritis safely increase physical activity, and improve physical and psychological health and HRQOL. Clinical Trials NCT00349869.