Drug desensitization is the induction of temporary unresponsiveness to drugs, thereby allowing patients to be treated with medications to which they have presented hypersensitivity reactions. This procedure has been safely used in patients with IgE-mediated allergic reactions. In addition, it may also be effective in other immune-mediated drug reactions. A few cases of cyclosporine hypersensitivity have been reported, but there has been no report regarding desensitization of intravenous cyclosporine. We report the first case of successful desensitization of intravenous cyclosporine in a patient who presented multiple hypersensitivity reactions shortly after peripheral blood stem cell transplantation. (Korean J Asthma Allergy Clin Immunol 2008;28:59-63)