Omalizumab is a monoclonal antibody against immunoglobulin E and it has been used in treatment of difficult allergic asthma for many years now. Its effectiveness has been reported in numerous clinical trials. However, despite many observations of patients receiving omalizumab, optimal time of treatment has not been established so far. Current conclusions are that the therapy should last as long as possible. There are also scarce reports on lack of response to omalizumab after withdrawal and re‑starting the drug. This case report concerns a patient, whose asthma control significantly deteriorated after omalizumab withdrawal. However, the drug readministration led to no improvement, despite original good response to omalizumab.