Background: We tried to examine association between the prognostic intensive care unit (ICU) scores and red cell distribution width (RDW) for prediction of mortality in a cohort of ICU patients at a single centre in Turkey. Methods: This is a retrospective cohort study conducted in a 9-bed mixed ICU of a tertiary hospital from January to December 2013. One hundred and nine ICU patients requiring intensive care following an elective or emergent surgical procedure, trauma or medical severe disease were enrolled in the study. Demographic data, admission clinical parameters and Acute Physiology and Chronic Health Evaluation (APACHE) II, Sequential Organ Failure Assessment (SOFA), Simplified Acute Physiology Score (SAPS) II scores were collected. The primary outcome was ICU mortality which is defined as death before hospital discharge for any reason. Receivers operating characteristic (ROC) curves were used to examine the performance of variables in predicting ICU mortality. Results: There were significant positive correlations between RDW and APACHE II, SOFA and SAPS II scores. RDW levels were significantly higher in non-survivors (16.94±3.05 versus 15.62±2.82, p<0.001). The optimal cutoff value of RDW for prediction of mortality according to ROC analyses was 14.5. ICU mortality rate was 18.9% if RDW level was less than 14.5%; and 81.1 % if RDW level was greater than14.5%. Conclusions: We found that ICU mortality was higher RDW was greater than 14.5%. We also found positive correlation between RDW and ICU mortality scores.