Fibrocystic breast disease (FBD) is a benign condition that afflicts at least 50% of women of childbearing age. Because of the occurrence rate, the condition is sometimes referred to as a nondisease. The cause of FBD remains unknown, and treatment is only empirical. This article reviews normal breast anatomy and physiology, describes the morphological changes apparent in FBD, discusses current etiological theories and treatment modalities, and identifies nursing interventions relative to women with FBD.