Chronic kidney disease (CKD) results from a wide range of disease processes that vary in prevalence across the world. However, the manifestations and complications of CKD are broadly common to all causes of CKD and result from the accumulation of nitrogenous waste products, abnormal electrolyte, water, and acid-base regulation, and loss of regulated production of erythropoietin, renin, and vitamin D. This chapter provides an overview of the approach to the patient with CKD and then provides a structured description of the pathogenesis of the complications of CKD according to the organ or system affected, including the cardiovascular system, the liver and gastrointestinal tract, the endocrine system, the skin, the nervous system, and the blood.