Imatinibis a commonly used antiproliferative agent for treating chronic myelogenous leukemia and gastrointestinal stromal tumors, and it is also thought to be effective in other areas, such as rheumatologic diseases. It has been shown to improve glucose control in diabetic patients by lowering blood sugar, reducing HbA1c levels, and decreasing the need for diabetes medications. However, we present a rare occurrence of severe hyperglycemia and newly elevated HbA1c in a patient on imatinib with no prior history of diabetes. It underscores the need for further research to assess the safety and impact of imatinib on glucose metabolism.