OBJECTIVES:  Severe asthma is a major cause of morbidity and mortality around the world, associated with a heavy societal burden. The aim of this study was to evaluate the economic value of omalizumab in the treatment of adult patients with severe allergic asthma in Greece, from a societal perspective, based on data collected from a clinical trial (INNOVATE) and real-world evidence (RWE) from a prospective observational study conducted in Greece . METHODS:   A Markov cohort model was developed in Microsoft Excel to compare the costs and outcomes of omalizumab plus standard therapy (ST, primarily comprised ICS, LABA and SABA) versus ST alone. The time horizon was that of a lifetime. Both direct and indirect costs were incorporated. Health outcomes considered were Quality Adjusted Life Years (QALYs). Costs and QALYs were discounted annually at 3.5%. Unit costs were taken from publically available sources. Productivity losses were calculated based on published data, while utility values were taken from the INNOVATE study. Deterministic and probabilistic sensitivity analyses were undertaken to test the robustness of the model results. RESULTS:   The addition of omalizumab to ST led to an incremental cost per QALY gained of €27,888 based on INNOVATE trial and €27,255 based on the RWE. The model appeared to be most sensitive to changes in the time horizon and the age of retirement. Results of the probabilistic sensitivity analysis showed that the probability of omalizumab being cost effective was 58% and 84%, at a willingness to pay threshold of €30,000 and €40,000, respectively. CONCLUSIONS: Omalizumab appears to be a cost-effective treatment option for adult patients with severe allergic asthma compared with ST in Greece, confirmed by both trial and real-world data.