Acute cholecystitis (AC) and acute appendicitis (AA), independently, are among the most commonly diagnosed conditions in the emergency department (ED). However, their synchronous presentation is very rare. Here, we present a 31-year-old man with worsening right flank abdominal pain, nausea, and vomiting. Physical examination results were significant for moderate to severe right upper abdominal quadrant pain with a positive Murphy's sign and right lower quadrant pain with rebound. Workup in the ED revealed leukocytosis with a left shift, and the abdominal ultrasound and computerized tomography scan showed AA and AC. A literature review revealed a paucity of publications on concomitant AA and AC. Reporting new cases will contribute to improving our understanding of the biology, natural history, and management of this rare pathological combination.