A 56 year old postmenopausal patient underwent a right radical mastectomy for a stage I breast cancer. An adjuvant treatment with tamoxifen was planned, but, because of patient's choice, a regular administration of the endocrine treatment started only one year after the operation. After a very short period of drug administration, she developed a steroid responsive nephrotic syndrome. We have reviewed the international literature concerning drug-induced renal disease; this is the first case of a tamoxifen-induced nephrotic syndrome.