Background: Our aim in this study was to investigate the effects of the COVID-19 pandemic on acute appendicitis cases.Methods: This study was designed as a single-center, retrospective, and observational study. The patients were divided into three groups relative to the date of the first COVID-19 case in Turkey, which was March 10, 2020 (Group A: before the pandemic; Group B: pandemic period; Group C: the same period one year before the pandemic). A total of 413 patients were included in the study.Results: In terms of treatment modality, the rate of open appendectomy was significantly higher in group B (p<0.001). Rates of conversion to open surgery, as well as rates of complicated appendicitis were also significantly higher in group B (p=0.027, p=0.024, respectively). While there was no difference between the groups in terms of preoperative hospitalization duration (p=0.102), it was found that the duration of symptoms, operation time, and postoperative length of hospital stay were significantly higher in Group B (p<0.001, p=0.011, p=0.001, respectively). In addition, the complication rate in group B (8.9%) was also significantly higher than in the other two groups (p=0.023).Conclusion: We found that the rate of open surgery, the rate of conversion of laparoscopic surgery to open surgery, complication rates, mean operation time, and postoperative hospital stay were significantly higher in acute appendicitis patients that underwent surgery during the COVID-19 pandemic period. We believe that the main reason for this negative outcome is the late admission of the patients to the hospital.