Heart failure remain as major health problem worldwide, causing severe morbidity and high mortality. Strong relationship between cardiac disorders and kidney disorders that affect the patient's prognosis. Cardiorenal syndrome (CRS) is a group of symptoms due to acute or chronic damage to one of the organs, including the heart or kidneys, which will affect the function of other organs. The heart and kidney each play a role as a regulator of the body's hemodynamic balance. The kidneys produce urine based on that produced by glomerular filtration which depends on the level of renal perfusion and arteriolar blood pressure. CRS classified into five. The classification is based on the primary and secondary damage from CRS occurs in the heart, kidney or outside the heart and/or kidney. Understanding the pathophysiology of CRS benefit to comprehensively manage patients with such condition.