Introduction/Objective. Juvenile idiopathic arthritis (JIA) is the most frequent chronic inflammatory, rheumatic disease of childhood, associated with disturbance of bone mineral metabolism, which develops gradually and progressively, and if untreated eventually leads to osteoporosis in adulthood. The aim of our study was to evaluate bone mineral density (BMD) in patients with JIA treated with etanercept over a period of one year. Methods. The prospective cohort study included 94 JIA patients (66 female, 28 male), their median age being 14.77 years. BMD was measured by dual-energy X-ray absorptiometry on the lumbar spine. Disease activity was assessed using the American College of Rheumatology Pedi 50 criteria. Results. After one year of treatment with etanercept, we found a statistically significant increment in all osteodensitometry variables (p