Idiopathic granulomatous mastitis (IGM) is a rare condition of unknown etiology with nonspecific findings. We present an unusual case of IGM manifesting after breast biopsy in a 42-year-old Turkish woman. IGM should be considered in the differential diagnosis when mastitis, carcinoma, and systemic diseases have been excluded and especially in the setting of a postbiopsy infection that is not responsive to antibiotic therapy.