Mesenteric adenitis is a self-limited condition characterized by fever, localized right lower quadrant abdominal pain, and frequent leukocytosis, making it difficult to differentiate from appendicitis. We report a case of mesenteric adenitis in an 8-year-old boy who presented at the emergency department with right lower quadrant abdominal pain, diarrhea, and fever up to 40 degrees C. Acute appendicitis was initially suspected, but further abdominal ultrasound and contrast enhanced computed tomography studies showed a normal appendix with marked mesenteric adenopathy. Symptomatic treatment was given and pain and fever subsided 2 days later. Follow-up sonography showed resolution of adenopathy, confirming the diagnosis of mesenteric adenitis. The admission stool cultures grew Salmonella enterica serovar Enteritidis (S. Enteritidis). Unlike previous reports in western countries where Yersinia species prevails and was thought to be self-limited, S. Enteritidis carries potential risk for serious systemic complications, such as meningitis or septic arthritis. The isolation of this unusual microbiological species thus has both therapeutic and epidemiological implications for mesenteric adenitis in Taiwan.