Objective. To determine the demographics of subtalar arthritis, the response to intraarticular corticosteroid injection, and the injection complication rate in a clinic sample of children with juvenile idiopathic arthritis (JIA). Methods. A chart review was performed of all patients at a tertiary medical center who underwent subtalar corticosteroid injection during the past 5 years. Injection of 1 ml of triamcinolone hexacetonide or acetonide into the midsubtalar joint was performed using a lateral oblique approach under fluoroscopic guidance. Improvement was defined by enhanced foot inversion and eversion at the following office visit. Results. Thirty-eight patients underwent 55 subtalar injections during the study period. All 7 JIA subtypes were represented. Thirty-one patients (82%) had subtalar arthritis at time of JIA diagnosis and 32 (84%) had concomitant tibiotalar ankle arthritis. Improvement was observed following 34 (89%) of the initial 38 injections. The mean duration of improvement was 1.2 years (SD ± 0.9). Twenty patients (53%) developed hypopigmentation or subcutaneous atrophy. This complication was associated with a higher volume of injected corticosteroid per patient weight (p = 0.02) and with less efficacious injections (p = 0.04). Conclusion. Subtalar arthritis in children with JIA is common. Similar to other joints, subtalar arthritis responds to corticosteroid injection in approximately 90% of cases and often remains improved for greater than one year. Hypopigmentation and subcutaneous atrophy are frequent complications and are likely related to the dose of injected corticosteroid and possibly the accuracy of needle placement.