This chapter summarizes normal renal handling of phosphate, calcium and magnesium as well as renal acid-base handling, reviews the molecular pathophysiology and genetic aspects of hereditary tubular disorders affecting mineral handling, and describes the clinical and laboratory features of these tubulopathies including the associated bone disease. Hereditary tubular transport disorders comprise a group of diseases that lead to profound derangements in the homeostasis of electrolytes, minerals or organic solutes in the body, and are associated with significant morbidity. The molecular study of hereditary tubulopathies is very important in clarifying the genetic basis of disorders also in providing new and important insight into the function of specific transport proteins and into the physiology of renal tubular reclamation of solutes. Inorganic phosphate (Pi) is one of the most abundant anions in the human body, and plays a crucial role in skeletal mineralization and cellular metabolism. Among the organ systems and tissues involved in Pi homeostasis, the mammalian kidney serves as the major regulator of Pi balance, and is capable of modulating its Pi reabsorptive capacity according to the needs of the organism.