Objective: The aim of this study was to evaluate the clinical and histopathological features of 42 patients with unusual infectious agents detected in their appendectomy specimens.Material and Methods: Between January 1999 and November 2018, 2.754 patients underwent emergency or incidental appendectomy in our clinic, and their pathology reports were retrospectively reviewed. Unusual infectious agents or eosinophilic infiltration of the appendix were reported in the initial pathological examinations of 57 patients. The pathological slides of these patients were re-examined by histopathologists. The examinations revealed that 15 of these patients had no microscopic findings suggestive of parasitic infections. The remaining 42 patients with unusual appendiceal infectious agents were included into the study.Results: A total of 42 patients (25 females and 17 males) aged 18 to 75 years were included into this study. While 32 of these patients (76%) underwent emergency appendectomy with a presumed diagnosis of acute appendicitis (AAp), the remaining 10 patients underwent incidental appendectomy for various reasons. Twenty-two patients (52.4%) had histopathological changes consistent with AAp while 20 patients had no evidence of AAp. Histopathological examination revealed infection with Enterobius vermicularis in 38 of the patients, Taenia species in 2, and Ascaris lumbricoides and Actinomycesspecies in 1 patient each. A total of 24 patients were treated for infections with mebendazole (n= 20), albendazole (n= 1), niclosamide (n= 2), and amoxicillin (n= 1). Conclusion: Unusual infectious agents should be considered as factors potentially triggering AAp, especially in patients living in endemic areas. The appendiceal stump should be inspected for parasite residues.