Appendix vermiformis is found in various anatomical localizations. Localization of the appendix vermiformis has been suggested to affect the clinical findings and out- comes of acute appendicitis. Aimed at investigating the effect of retrocecal localization of appendix vermiformis on the prognosis of acute appendicitis today. This study was started in August 2018 and finished in August 2021. Adult patients of both sexes who were operated in general surgery clinic with a pre-diagnosis of acute appendicitis were included in the study. Anatomic localization of appendix vermiformis were divided into two parts as retrocecal localizations and non-retrocecal localizations. The forms of appendicitis, postoperative complications, and length of hospitalization obtained from retrocecal and non-retrocecal localizations were compared and evaluated. A total of 776 patients were included in the study. Retrocecal localization was found in 15%, and non-retrocecal in 84.9% of the patients. The rate of acute appendicitis was 65.8% in retrocecal localization, 83.1% in non-retrocecal localization, perforated appendicitis at 31.6% in retrocecal localization and 11.2% in non-retrocecal localization. The perforated appendicitis rate was significantly higher in retrocecal localizations (p=.0001). Although postoperative complications were 5.1% in retrocecal appendicitis and 2.4% in non-retrocecal appendicitis, there was no significant difference between them in terms of postoperative complications (p=.105). The mean length of hospital stay was 2.4 days for appendicitis with retrocecal localization and 1.7 days for non-retrocecal localizations. The mean length of hospital stay was also significantly higher in retrocecal localizations (p=.0001). In conclusion, both perforated appendicitis rates and the mean length of hospital stay were higher in appendicitis with retrocecal localization. Therefore, appendicitis with retrocecal localization still negatively affects the prognosis of acute appendicitis today.