The embryology, anatomy, and physiology of the multi-functional proximal renal tubule, thick descending tubule, thin, and thick ascending limbs of the loop of Henle, distal convoluted tubule, connecting tubule, and collecting duct are described. The clinical manifestations and biochemical abnormalities of the four forms of renal tubular acidosis (RTA: Type 1 – Distal tubule, Type 2 – Proximal tubule, Type 3 – Mixed, Type 4 – Hypoaldosteronism) are presented. Forms of pseudohypoaldosteronism are then reviewed. The pathophysiology and genetic variations underlying the Bartter, Gittleman, Liddle, and Fanconi syndromes are presented.