Herpes zoster is an infectious disease caused by varicella-zoster virus that may occur sporadically at any age. We report on two patients with herpes zoster who received chemotherapy for breast cancer. Both patients were immunocompromised and received filgrastim therapy for the management of neutropenia. Zoster occurred during filgrastim therapy but the symptoms were alleviated rapidly in the course of therapy. We conclude that granulocyte colony-stimulating factor therapy helped symptom alleviation and accelerated the recovery from herpes zoster in our chemotherapy-treated patients. Free full text available at www.tumorionline.it