BACKGROUND Severe Pediatric Allergic Asthma (SPAA) induces a huge economic burden in terms of direct, indirect and intangible costs. The use of omalizumab for the treatment of these patients has produced a significant improvement in several clinical outcomes, but at the same time, the cost for the management of the disease has also increased. The aim of this report was to evaluate whether the use of omalizumab is cost-effective. METHODS A sample of 426 children with SPAA from the ANCHORS study was used to calculate the Incremental Cost Effectiveness Ratio (ICER) for the avoidance of Moderate to Severe Exacerbations (MSE), and also for the improvement in childhood Asthma Control Test (c-ACT) or the Asthma Control Questionnaire (ACQ5). We retrospectively collected data of health encounters and drug consumption before and up to six years after the beginning of the treatment with omalizumab. RESULTS The ICER per avoided MSE was \euro2,107 after one year, and it consistently decreased to \euro656 in those followed up to six years. Similarly, the ICER for the Minimally Important Difference in control tests showed a decrease from \euro2,059 to \euro380 per each 0.5 points of improvement in ACQ5, and from \euro3,141 to \euro2,322 per each 3 points improvement in c-ACT, at years 1 and 6 respectively. CONCLUSION The use of OMZ is a cost-effective option for most children with uncontrolled SPAA, mainly those who have frequent exacerbations, showing progressively reduced costs in successive years of treatment.