The solute carrier family 12, as numbered according to HUGO nomenclature, encodes the electroneutral cation-coupled chloride cotransporters that are expressed in many cells and tissues; they play key roles in important physiological events, such as cell volume regulation, modulation of the intracellular chloride concentration and transepithelial ion transport. Most of these family members are expressed in specific regions of the nephron. The Na+:K+:2Cl- cotransporter NKCC2 in the thick ascending limb and the Na+:Cl- cotransporter in the distal convoluted tubule play a key role in salt reabsorption and serve as the receptors for loop and thiazide diuretics, respectively, which are among the most commonly prescribed drugs in the world. The activity of these transporters correlates with blood pressure levels; thus, their regulation has been a subject of intense research for more than a decade. The K+:Cl- cotransporters KCC1, KCC3, and KCC4 are expressed in several nephron segments, and their role in renal physiology is less understood but nevertheless important. Evidence suggests that they are involved in modulating proximal tubule glucose reabsorption, thick ascending limb salt reabsorption and collecting duct proton secretion. In this work, we present an overview of the physiological roles of these transporters in the kidney, with particular emphasis on the knowledge gained in the last few years.