Denosumab is a human monoclonal antibody indicated for the treatment of osteoporosis in postmenopausal women with a high risk of fractures. To our knowledge, no cases of desensitization to this drug have been described in the literature. We report the first case of generalized urticarial reaction and facial angioedema after therapy with denosumab. A subcutaneous desensitization protocol was successfully completed in this patient. Rapid desensitization is a promising method for the delivery of denosumab after a hypersensitivity reaction, and should be considered in osteoporosis treatment when no acceptable therapeutic alternatives are available.