Abstract: Objective To explore the clinical features of patients with acute kidney injury (AKI) in the internal medicine departments.Methods The kidney function indexes of the internal medicine patients were collected in Shanghai Changzheng Hospital from 2011 to 2012. According to the AKI diagnostic criteria of KDIGO in 2012, we screened out the AKI patients who met the criteria. By retrospectively studying their clinical data, we analyzed and summarized their clinical characteristics and the factors affecting the prognosis.Results From January 2011 to December 2012, there were a total of 33 332 cases of internal medicine patients in our hospital and 245 of them met the criteria of AKI. The incidence of AKI was 0.74% in internal medicine departments while the detection rate of AKI was 35.92%. The proportions of patients with AKI stage 1 to 3 were 42.45%, 20.41% and 37.14%, respectively. Among all the internal medicine departments, patients in the department of nephrology accounted for 33.47%, followed by the department of cardiology (20.00%), gastroenterology (11.84%) and infectious disease (10.61%). The incidence of AKI from high to low was infection disease department (1.70%), nephrology department (1.37%), and cardiology department (1.11%). Of all the hospitalized patients with AKI, 71.84% discharged with a better health condition and the kidney function discovered in only 34.69% of the discharged patients; 28.16% died or gave up treatment. The most common departments with high fatality rate were the department of infectious disease (21.74%), gastroenterology and cardiology. Infection was the main cause of the AKI in internal medicine departments. Logistic regression analysis showed that higher AKI stage, more AKI risk factors, combination with liver disease or tumor were risk factors for death and giving up treatment, while chronic kidney disease was the protective factor.Conclusions AKI is common in internal medicine system, with a high mortality rate and a higher recognition rate than perioperative AKI. Except for the department of nephrology, cardiology, departments of infectious disease and gastroenterology have heavy burden of AKI. The advanced stage of AKI, more risk factors, and comorbidities such as liver disease or tumor were associated with poor prognosis.