Imatinib mesylate (also known as Gleevec) is a selective tyrosine kinase inhibitor, primarily used for the treatment of chronic myeloid leukemia and gastrointestinal stromal tumors. Despite its effectiveness, the use of imatinib has been associated with various adverse skin reactions such as maculopapular rash, edema, and lichenoid or psoriasiform lesions. We report the case of a 71-year-old female presented with follicular hyperkeratotic papular eruption that affected her entire body. The lesions had developed 2 weeks ago. The patient had been diagnosed with a malignant gastrointestinal stromal tumor and had been receiving imatinib mesylate since 2013. Three weeks before the onset of the skin eruptions, the imatinib dosage was increased to 800 mg/d. Skin biopsies were performed on the chin and forearms. Based on the clinical and histopathological results, the patient was diagnosed with imatinib-induced keratosis pilaris. Following the discontinuation of imatinib and retinoid therapy, her skin condition markedly improved, and the lesions resolved within a few weeks. Herein, we report a case that highlights the association between imatinib mesylate and keratosis of the pilaris.