To evaluate the clinical and demographic characteristics of patients with juvenile idiopathic arthritis (JIA) in Chile and compare treatments and outcomes before and after the introduction in 2010 of the Explicit Health Guarantees (GES) for JIA, a national universal access program for diagnosis and treatment of this condition. The clinical records of 280 patients with JIA followed at a private tertiary academic health network between 2007 and 2018 were reviewed. Seventy percent of patients with JIA were female, mean age at diagnosis was 8.5 ± 4.8 years and mean follow-up was 4.0 ± 3.7 years. After GES implementation (post-GES), time to evaluation by pediatric rheumatologist and diagnostic delay were significantly reduced (15.0 ± 4.5 vs 9.0 ± 4.2 months, P = 0.004). In addition, use of magnetic resonance imaging significantly increased post-GES (P < 0.001). In terms of JIA treatments, before GES implementation, no patients received biologics. Of the 67 patients diagnosed before 2010 with continued follow-up at our center, 34% began biologic treatment after GES implementation. Of 196 patients diagnosed post-GES, 46% were treated with biologics. JIA remission rates were significantly higher in patients diagnosed post-GES compared to pre-GES (43% vs 29%, P = 0.02). Post-GES, we observed a significant decrease in uveitis complications among JIA patients (45% vs 13%, P = 0.04). The implementation of a national government-mandated universal access program for guaranteed JIA diagnosis and treatment led to earlier access to a pediatric rheumatologist and JIA diagnosis, increased rates of treatment with biologic drugs, higher rates of clinical remission, and lower rates of uveitis complications in Chilean children with JIA.