The aim of the present study was to investigate the significance of appendicoliths as an exacerbating factor of acute appendicitis using multivariate analysis. A total of 254 patients with pathologically proved acute appendicitis were enrolled in this retrospective study (male, 51 %; mean age, 40.1 years; range, 15–91 years). Two radiologists performed a consensus evaluation of preoperative CT images for the presence of appendicoliths in consensus. When there were appendicoliths, they assessed the number and location of appendicoliths, and measured the longest diameter of the largest appendicolith. Pathological diagnosis was used for the reference standard. The relationships of appendicoliths to gangrenous appendicitis and to perforated appendicitis were each assessed with multiple logistic regression models, which were adjusted for demographic and clinical characteristics of patients. Significant relationships were identified between gangrenous appendicitis and the presence of appendicoliths (OR, 2.2; 95 % CI, 1.2–4.0), the largest appendicolith more than 5 mm in the longest (OR, 3.0; 95 % CI, 1.6–5.7), and location of an appendicolith at the root of the appendix (OR, 2.0; 95 % CI, 1.1–3.8). Among the CT characteristics, the location of an appendicolith at the root of the appendix only showed significant relationship with perforated appendicitis (OR, 4.5; 95 % CI, 1.4–15.4). Size of the largest appendicolith and location of appendicoliths at the root of the appendix are exacerbating factors of acute appendicitis.