Carbon monoxide (CO) is an odorless, colorless, and nonirritating gas. Acute CO poisoning is known as a major cause of mortality and morbidity worldwide throuth the previous study. CO intoxication have various clinical manifestations by tissue hypoxia and direct cell damage. There are some reports regarding neurologic complications and cardiac injury after CO poisoning but no report about the kidney injury. The aim of this study was to investigate general characteristics and prognosis in patients who had kidney injury after CO poisoning. A retrospective study was conducted on consecutive patients who were diagnosed with acute CO poisoning at the emergency department of the Wonju Severance Christian Hospital, Wonju College of Medicine, Yonsei Univeristy, Wonju, Korea from January, 2006 to March, 2012. We defined liver injury after CO poisoning as the Creatinine (Cr) level of more than 1.4mg/dL. Exclusion criteria were age < 18, previous kidney disease. The total of 370 patients was enrolled. The elevation of serum Cr was seen in 11 patients (2.97%). Total admission day was 25.82±12.71, 3.96±0.92 (p<0.001) and ICU admission day was 9.64±7.26, 1.12±0.43 (p<0.001) in acute kidney injury group and in normal group respectively. Acute kidney injury group have more incidence rate of severe complications ; Rhabdomyolysis (p=0.001), Pneumonia (p<0.001), Mental change (p<0.001), and more longer Hospital day ; General ward (p=0.001), ICU (p=0.001) and more Mortality (p<0.001). 11 patients (2.97%) showed elevated Cr following CO poisoning. Total admission and ICU length was longer in acute kidney injury group than non-Cr elevation group. The severity and mortality were increased more in acute kidney injury group than non-Cr elevation group.