['Sepsis is a pro-inflammatory state caused by systemic infection. As sepsis progresses, multiple organ systems become affected with subsequent increase in mortality. Elevated red cell distribution width (RDW) has been seen with changes of other inflammatory markers and thus could potentially serve as a means of assessing sepsis severity. In this study, we examine the association of RDW with APACHE II score and in-hospital mortality.', 'We conducted a retrospective study involving a cohort of patients with sepsis. The study period spanned 2 years with a cohort of 349 patients. Data were collected to determine if RDW is associated with APACHE II scores and in-hospital mortality in this cohort.', 'RDW correlated weakly (r s = 0.27), but significantly (P < 0.0001) with APACHE II scores; coefficient of determination (r (2) = 0.09). The odds ratios for the association of RDW with APACHE II were calculated over the RDW range 12-20% at a dichotomized level of APACHE II, i.e., <15 and ≥15. At a RDW ≥16%, multivariate analysis including all potential confounders indicated that RDW was independently associated with an APACHE II score of ≥15. Similarly, mortality was associated with RDW ≥16%.'] Is broadening of the red blood cell distribution width associated with increased severity of illness in patients with sepsis?