Although anemia and Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD) are two apparently different fields of medicine, there are more intertwined than previously thought of. In this lecture, we will discuss the critical role of iron and erythropoietin (EPO) in the regulation of fibroblast growth factor 23 (FGF23), the master regulator of the phosphate and vitamin D homeostasis. The following topics will be highlighted: the discovery of the link between iron deficiency and FGF23; the different effects of iron deficiency and EPO on intact and C-terminal FGF23 levels; the consequences of certain iron preparations on FGF23; and the effect of the new medication class in the treatment of renal anemia, i.e., hypoxia-inducible factor prolyl hydroxylase inhibitors (HIF-PHI) on FGF23 levels. Finally, the current literature regarding the bidirectional nature of the interplay between iron, EPO, and FGF23 will be mentioned, as FGF23 is also implicated as an important regulator of erythropoiesis and iron metabolism.