The aims of the study were to assess efficacy and safety of TNF-alpha antagonists (anti-TNF) in a cohort of patients with juvenile idiopathic arthritis (JIA) who began treatment under 4 years old and to assess relapse rate after methotrexate and/or anti-TNF withdrawal. We made a retrospective charts review of our non-systemic JIA patients treated with anti-TNF under 4 years of age between January 2006 and April 2013. Demographics, epidemiologic, clinical, laboratory data and rate of relapse after treatment withdrawal due to clinical remission were collected. Efficacy and safety end points included side effects (SE) and time to achieve clinical remission. We included 27 patients, 23 received etanercept and 4 adalimumab with a median age of 3.01 (range 0.88-3.97) years at anti-TNF beginning and 1.94 (range 0.18-5.44) and 2.39 (range 0.18-7.24) years of treatment and follow-up, respectively. All patients had previously received disease-modifying antirheumatic drugs at optimal dose. Nineteen patients reached clinical remission on treatment in a median time of 9.1 (range 6.23-21.17) months. Four of those relapsed during treatment. Six developed mild SE, mostly mild infections. No serious SE were described. Eleven patients who reached clinical remission relapsed after treatment withdrawal. None achieved clinical remission off treatment. Most patients reached clinical remission on anti-TNF. In our cohort of patients, etanercept and adalimumab were safe, with mostly mild infections and no serious SE. We observed a high relapse rate during treatment withdrawal.