Aims: This study aims to define characteristics of hypersensitivity reactions with etoposide, and outcomes of desensitizations in immediate-type hypersensitivity rections
 Methods: This is a retrospective observational study of patients who had hypersensitivity reactions with etoposide from January 2019 to December 2023. 
 Results: A total of 39 patients with lung cancer were included in the study. Ten (25.6%) patients had known other drug allergies and three (7.7%) patients had previous chemotherapeutic hypersensitivity two with paclitaxel and one with docetaxel. Most of the initial hypersensitivities were in the first or second cycle (n=29, 74.4%). Ten (25.4%) patients had hypersensitivity reactions at the first application of etoposide. Thirty (76.9%) patients had immediate-type hypersensitivity reactions. There was no significant difference in terms of patient and initial hypersensitivity characteristics between patients who had immediate or non-immediate type hypersensitivity reactions. Of the 30 patients with immediate-type hypersensitivity reactions, initial reaction was mild in 16 (53.3%) and moderate in 14 (46.7%) patients. Most common symptoms were erythema in 29 (96.7%), dyspnea in 13 (43.3%), chest tightness in 8 (26.7%), discomfortness in 7 (23.3%), and hypertension in 6 (20%). Skin tests were negative in five patients who underwent skin testing. A total of 98 desensitization courses were performed in 27 patients and 3 (11.1%) patients had breakthrough reactions.
 Conclusion: Most of the hypersensitivity reactions to etoposide are immediate-type and not severe. Desensitization is an effective and safe procedure to manage these reactions. Further research is needed to elucidate the mechanisms of hypersensitivity reactions.