BACKGROUND Duplex or vermiform appendix refers to the presence of an appendix beside the naturally occurring one. Although, duplex appendix emerges from the caecum most of the time, yet it is encountered in other parts of the colon. Inflammation of duplex appendix may represent not only a clinical, but also a surgical dilemma, and this would be confusing further among patients who already had prior appendectomy. METHODS We present a case of 29-years old Egyptian male patient with history of appendectomy one and half year before presenting to the emergency department with recurrent acute abdominal pain that was linked to duplex appendicitis abnormally emerged from the mid-ascending colon. The first episode was treated conservatively considering atypical right colon diverticulitis as a potential differential diagnosis. Seven months later the patient was treated by laparoscopic appendectomy and experienced an uneventful pot-operative course. CONCLUSIONS Duplex appendicitis, though rare, should be considered in the differential diagnosis of recurrent acute abdomen even after appendectomy.