Cardiorenal syndrome, a complex pathophysiological disorder of both the heart and kidneys, is a condition in which acute or chronic damage to one organ can lead to acute or chronic dysfunction of the other organ. Depending on primary organ dysfunction and disease duration, there are five different types of cardiorenal syndrome. Type 1 cardiorenal syndrome (acute cardiorenal syndrome) is defined as acute kidney injury caused by sudden decrease in heart function. Type 2 cardiorenal syndrome (chronic cardiorenal syndrome) refers to chronic kidney disease linked to chronic heart failure. Type 3 cardiorenal syndrome (acute renocardial syndrome) is caused by acute kidney injury that leads to heart failure. Type 4 cardiorenal syndrome (chronic renocardial syndrome) includes chronic heart failure due to chronic kidney disease. Type 5 cardiorenal syndrome (secondary cardiorenal syndrome) is reversible or irreversible condition marked by simultaneous heart and kidney insufficiency, as a result of multiorgan disease such as sepsis, diabetes mellitus, sarcoidosis, amyloidosis, etc. The pathophysiological patterns of cardiorenal syndrome are extremely complicated. Despite numerous publications, perplexed physiological, biochemical and hormonal disturbances as parts of the main pathogenic mechanisms of cardiorenal syndrome remain obscure. Even though there are guidelines for the treatment of patients with heart failure and chronic kidney disease, similar guidelines for the treatment of cardiorenal syndrome are lacking. In everyday practice, it is crucial to diagnose cardiorenal syndrome and use all diagnostic and therapeutic procedures available to prevent or alleviate kidney and heart failure.