In December 2019, a coronavirus 2019 (COVID-19) outbreak, caused by SARS-CoV-2, took place in Wuhan and was declared a global pandemic in March 2020 by the World Health Organization (WHO). It is a prominently respiratory infection, with potential cardiological, hematological, gastrointestinal and renal complications. Acute kidney injury (AKI) is found in 0.5%-25% of hospitalized COVID-19 patients and constitutes a negative prognostic factor. Renal damage mechanisms are not completely clear. We report the clinical evolution of hospitalized COVID-19 patients who presented with AKI requiring attention from the Nephrology team in a tertiary hospital in Madrid, Spain. This is an observational prospective study including all COVID-19 cases that required hospitalization and Nephrology management from March 6th to May 12th. We collected clinical and analytical data of baseline characteristics, COVID-19 and AKI evolutions. We analyzed 41 patients with a mean age of 66.8 years (SD 2.1), 90.2% males, and with a history of chronic kidney disease (CKD) in 36.6%. 56.1% of patients presented with sever pneumonia or acute respiratory distress syndrome (ARDS), and 31.7% required intensive care. AKI etiology was prerenal in 61%, acute tubular necrosis in the context of sepsis in 24.4%, glomerular in 7.3% and tubular toxicity in 7.3% of the cases. We reported proteinuria in 88.9% and hematuria in 79.4% of patients. 48.8% of patients required renal replacement therapy (RRT). Median length of stay was 12 days (interquartilic range 9-23) and 22% of the population died. Patients who developed AKI during hospital stay presented with higher C-reactive protein, Lactate dehydrogenase-LDH and d-dimer values, more severe pulmonary damage, more frequent intensive care unit-ICU admission, treatment with lopinavir/ritonavir and biological drugs and RRT requirement. Hypovolemia and dehydration are a frequent cause of AKI among COVID-19 patients. Those who develop AKI during hospitalization display worse prognostic factors in terms of pulmonary damage, renal damage, and analytical findings. We believe that monitorization of renal markers as well as individualized fluid management can play a key role in AKI prevention.