This article reviews the pathogenesis of diabetic ketoacidosis (DKA) and provides a rational approach to the management of patients with DKA. The therapeutic discussion includes the use of low-dose insulin, no bicarbonate, or phosphate therapy on the majority of DKA patients, based on numerous prospective randomized studies. The article also discusses controversial subjects such as the use of hypotonic versus isotonic saline with and without colloids, hydration of subjects before insulin therapy, and admission of DKA patients to the general ward versus emergency ward versus intensive care unit. A concise, simple protocol is also presented as a suitable reference for management of patients with DKA.