Fecal appendicular peritonitis (FAP) is a poorly studied, rare form of acute appendicitis, corresponding to peritoneal inflammation with the presence of feces secondary to ruptured appendix. The purpose of this study was to describe FAP and to compare FAP with purulent appendicular peritonitis (PAP). This single-center, retrospective study was conducted in consecutive patients to compare the FAP group and the PAP group. The primary endpoint was the 30-day postoperative morbidity and mortality according to the Clavien-Dindo classification. The secondary endpoints were description and comparison of intraoperative data (laparoscopy rate, conversion rate, type of procedure and the mean operating time), and short-term outcomes (types of complications, length of stay, readmission rate, and reoperation rate), comparison of intraoperative bacteriological samples of FAP and PAP as well as the rate of resistance to amoxicillin and clavulanic acid, used as routine postoperative antibiotic therapy. Between January 2006 and January 2016, 2.2% of appendectomies were performed for FAP. Patients of the FAP group reported a longer history of pain than patients of the PAP group (mean: 58 h [range: 24-120] vs 24 h [range: 6-504], p = 0.0001) and hyperthermia was more frequent in the FAP group than in the PAP group (72% vs 26%, p = 0.0001). Mean preoperative CRP was also higher in the FAP group than in the PAP group (110 mg/L [range: 67-468] vs 37.5 mg/L [range: 3.1-560], p = 0.007). Significantly less patients were operated by laparoscopy in the FAP group (89.7% vs 96.6%, p < 0.0001). Mean length of stay was significantly longer in the FAP group than in the PAP group (10 days [range: 3-24] vs 5 days [range: 1-32], p = 0.001). The overall 30-day complication rate was significantly higher in the FAP group than in the PAP group (62.1% vs 24.7%, p = 0.0005). The readmission rate was not significantly different between the two groups (14% vs 11.2%, p = 0.2), but the reoperation rate was higher in the FAP group than in the PAP group (31% vs 11%, p = 0.01). No significant difference was observed between the FAP and PAP groups in terms of the positive culture rate (75.9% vs 65.6%, p = 0.3). No significant difference was observed between the two groups in terms of resistance to amoxicillin and clavulanic acid (18.2% vs 20.5%, p = 0.8). FAP is associated with significantly more severe morbidity compared to PAP. Clinicians must be familiar with this form of appendicitis in order to adequately inform their patients.