To characterize the effect, if any, of imatinib mesylate, an inhibitor of abl tyrosine kinase used in the treatment of chronic myeloid leukemia, on type 2 diabetes.The centralized pharmacy database was used to identify all patients who had received imatinib at the Mayo Clinic in Rochester, Minnesota, during a 5-year period. The electronic medical records were subsequently reviewed to identify which of these patients had type 2 diabetes. In addition, relevant biochemical data, prior to, during, and after imatinib treatment, were abstracted from the electronic laboratory database and medical records.At the Mayo Clinic in Rochester, Minnesota, a total of 164 patients received imatinib during the period of study (1999 to 2004). Of these 164 patients, 7 had preexisting type 2 diabetes, and diabetes developed in 2 patients during treatment with imatinib. Despite 2 previous reports of improvement in glycemic control with use of imatinib in patients with type 2 diabetes, no net effect on glycemic control or diabetes therapy was noted in our study cohort.On the basis of our current study, it seems unlikely that imatinib substantially affects glycemic control in patients with type 2 diabetes.