Objective: The red blood cell distribution width (RDW) has recently been used as a marker to predict outcome in various patient groups. In this study, we aimed to examine how RDW is influenced during the treatment and followup of cases of acute cholecystitis which is a common inflammatory disease. Material and Methods: Seventy-two patients who were treated for acute cholecystitis, were included into the study. The demographic data, leukocyte count, RDW, C-reactive protein (CRP) values and treatment protocols of these patients were prospectively recorded. The patients who received medical treatment for acute cholecystitis (Group A, n=33) and those who underwent surgery (Group B, n=39) were examined in separate groups. Results: There were 27 male and 45 female patients with a mean age of 50.1±18 years (min-max: 21-94). In Group B, 33 patients received laparoscopic cholecystectomy, and 6 patients underwent open cholecystectomy. The RDW values on admission were not significantly different between two groups. However the post-treatment and predischarge RDW values were significantly lower in the surgical group (respectively: 14.4±1.9 to 13.6±1.1; p<0.05). Also, no significant RDW change was identified in the medical treatment group based on an intra-group assessment, whereas a significant decrease was observed in Group B (on admission and following surgical treatment, respectively: 14.3±1.3, 13.6±1.1, p=0.015). No significant differences were observed between groups in terms of CRP and leucocyte values. Conclusion: There was a significant decrease in RDW values in patients who were treated with surgery for acute cholecystitis, while this response could not be observed with medical treatment.