Background: Imatinib is a new major treatment in chronic myeloid leukemia. Objective: To study the cutaneous reactions induced by imatinib. Methods: All inpatients and outpatients with Philadelphia chromosome-positive leukemia treated by imatinib were included in this prospective study. Clinical features, pathologic findings, evolution of each case, and analysis of potential risk factors were recorded. Results: A total of 54 patients were included, 48 of whom experienced at least 1 cutaneous reaction. These reactions consisted of 36 rashes, 35 edemas, and 22 pruritus. The rash was severe in 5 patients, resulting in temporary interruption of treatment in 3. Highly significant relationships were observed between the daily dose of imatinib and both rashes and edema. In a multivariate analysis, female sex and the daily dose of imatinib were independent risk factors for the development of rashes. Conclusion: Adverse cutaneous reactions induced by imatinib are frequent, generally moderate, and dose-dependent. (J Am Acad Dermatol 2003;48:201-6.)