Relevant interest has been focused on rapid desensitization for drug hypersensitivity and on its use for reactions to monoclonal antibodies. Natalizumab is a highly effective therapy for multiple sclerosis but its use can be limited by hypersensitivity reactions. Herein we present a case of a 36-year-old male patient with multiple sclerosis who started natalizumab therapy due to rapid neurological deterioration. During the second infusion he developed a reaction involving urticaria, erythema and angioedema. Natalizumab sensitization was demonstrated by a positive result on the intradermal test. The anti-natalizumab IgG neutralizing antibody assay was negative. Lacking any alternative, equally effective treatment, he underwent a rapid intravenous desensitization protocol. Desensitization was successfully repeated eleven times and the patient's neurological conditions improved and remained stable after one year. This case demonstrates that rapid desensitization is a safe and effective procedure in the treatment of natalizumab hypersensitivity.