Diabetic fibrous mastopathy was first described in 1984. This mastopathy usually occurs in patients with autoimmune disorders and often occurs in patients with insulin-dependent diabetes. Little is known about this benign condition. Clinically and radiologically, this entity may simulate malignancy. The presence of an underlying auto-immune disorder or diabetes may suggest the correct diagnosis. The authors report two cases of fibrous mastopathy and suggest that core biopsy could replace surgical biopsy for diagnosis.