Cardiorenal Syndrome Type 1 (CRS-1) is defined as an acute worsening of heart function leading to acute kidney injury and/or dysfunction. It is an important cause of hospitalization which affects the diagnosis as well as the prognosis and treatment of patients. The purpose of this paper is to analyze causes that lead to the development of cardiorenal syndrome type 1 and its clinical consequences, as well as to emphasize the clinical importance of its early detection. The clinical studies and professional papers dealing with etiopathogenesis, diagnosis and treatment of cardiorenal syndrome type 1, have been analyzed. The most important role in the occurrence of cardio renal syndrome type 1 is played by hemodynamic mechanisms, activation of neurohumoral systems, inflammation and imbalance between the production of reactive oxygen species (ROS) and nitric oxide (NO). Diagnosis of cardiorenal syndrome type 1 involves biomarkers of acute renal injury among which the most important are: neutrophil gelatinaseassociated lipocalin (NGAL), cystatin C, kidney injury molecule 1 (KIM-1), liver-type fatty acid binding protein (L-FABP), IL-18 and the values of nitrogen compounds in serum. In addition to a pharmacological therapy, various modalities of extracorporeal ultrafiltration are applied in treatment of CRS-1, particularly if there is resistance to the use of diuretic therapy. As opposed to the experimental models, in clinical practice acute renal injury is often diagnosed late so that the measures taken do not give the expected results and the protective role shown in experimental conditions do not give the same results. For all these reasons, it is necessary to analyze the pathophysiology of renal impairment in cardiorenal syndrome as well as detect early indicators of kidney injury that could have clinical benefit and positive impact on reducing the cost of treatment.