Objective: The aim of this study was to evaluate the diagnosis of sarcopenia by abdominal tomography, prevelance and prognosis in critical patient admitted to intensive care unit(ICU). Methods: It was planned as a retrospective observational study. Patients older than 40 years of age with abdominal tomography who needed to be in the ICU were included. Muscle mass was measured by abdominal tomography. All patients were divided into two groups as sarcopenic and non-sarcopenic according to the measurement results. We compared the prognosis and clinical features of patients with and without sarcopenia. Results: Fifty five(59%) of all patients were found as sarcopenic and 70.8% over 70 years of age. The length of stay in ICU and in hospital were 27.8 ± 29.7 and 33.0 ± 31.2 days in sarcopenic patients, 15.1±17 and 23.8±21.3 days in nonsarcopenic patients respectively(p <0.05). Thirty day mortality was found 49.1% in patients sarcopenic(<0.05). SMI was found lower over aged 70 years(p <0.05). Conclusions: Sarcopenia was associated with the increasing of 30 day mortality, a prolongation in the lenght of stay in ICU and hospital. Therefore, we believe that awareness about sarcopenia will be important in order to shorten the mortality and lenght of stay in ICU.