Situs inversus totalis is a rare inherent disease in which the thoracic and abdominal organs are transposed. Symptoms of appendicitis in situs inversus (SI) may appear in the left lower quadrant, and the diagnosis of appendicitis is very difficult. We report a case of left-sided appendicitis diagnosed preoperatively after dextrocardia that was detected by chest X-ray, although the chief complaint of the patient was left lower-quadrant pain. The patient underwent an emergent laparoscopic appendectomy under the diagnosis of appendicitis after abdominal computed tomography (CT). In patients with left lower quadrant pain, if the chest X-ray shows dextrocardia, one should suspect left-sided appendicitis. A strong suspicion of appendicitis and an emergency laparoscopic operation after confirmation of the diagnosis by imaging modalities including abdominal CT or sonography can reduce the likelihood of misdiagnosis and complications including perforation and abscess. Laparoscopic appendectomy in SI was technically more challenging because of the mirror nature of the anatomy.