Enterobius vermicularis is the most common parasitic worm responsible for gastrointestinal infection worldwide. Acute appendicitis due to E. vermicularis is a rare infection, affecting mostly the children. In this report, we present the case of a 5-year-old girl infant infected by E. vermicularis found in the appendix lumen. A couple of histopathological and parasitological analyses followed by imaging allowed us to diagnose accurately the etiologic agent. Clinicians should be aware of this parasitosis as a possible cause of acute appendicitis.