Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection. The incidence of sepsis are between 300 to 1000 cases per 100,000 people per year. Red cell distribution width (RDW) is an index variation of RBC volume, which is a cost-effective and easy tool for predicting the prognosis of critically ill patients. RDW value can be used as an independent indicator of mortality in septic patients. Sepsis can increase RDW through various mechanisms, such as the role of inflammatory mediators, which directly induce red blood cell damage, increased nitric oxide (NO) levels, which play a role in interfering with the deformability of erythrocyte membranes, and oxidative stress, which can interfere with erythropoiesis, thereby increasing the production of premature erythrocytes, reduce the survival of erythrocytes, interfere with the deformability of the erythrocyte membrane, and erythrocyte half-life. Retrospective with a cross-sectional study design. Data were taken from the medical records. The severity of sepsis was assessed by the SOFA score, and RDW was taken from routine blood data. Data analysis used SPSS version 22 and Pearson's correlation test. There is a significant correlation between the SOFA score and RDW with p value 0.000 (p<0.05). The resulting coefficient is +0.510, there is a linear correlation with moderate strength between the SOFA score and RDW. There is a significant correlation between the severity of sepsis as assessed by the SOFA score and RDW.