Inherited abnormalities of renal tubular transport processes encompass a heterogeneous set of disorders due to single gene defects. Elucidating the molecular basis for these generally rare disorders has provided important insights into disease pathogenesis as well as the complexities of normal renal transport physiology. This review focuses on the clinical features and recent molecular advances in cystinuria, X-linked hypophosphatemic rickets, and the Bartter-Gittelman spectrum of disorders. Also addressed are disorders of calcium homeostasis resulting from loss-of-function and gain-of-function mutations of the extracellular calcium-sensing receptor, as well as the single gene defects that cause distal renal tubular acidosis.