From January 2001 to December, 2011, 8 patients were operated at National Hospital of Pediatrics with preoperative diagnosis appendicitis but final diagnosis omental disease. There were 4 boys and 4 girls with mean age of 5.4 years. All 8 patients had clinical presentations indistinguishablle from appendicitis. Routine blood tests and abdominal ultrasound were un useful for making the exact diagnosis. Laparoscopic surgery was performed find intra - operatively omental torsion was found in 7 cases and omentitis in one case, all with normal appendix. After resection of the involved part of the omentum, all patients recovered smoothly without complication with mean postoperative stay of 3.8 days. Therefore primary omental torsion or omentitis in children can present clinically like acute appendicitis and the accurate diagnosis is usually made intra - operatively. Laparoscopic surgery with advantages of mini - invasiveness and ability to explore entire abdominal cavity is an ideal means for both diagnosis and treatment for these diseases.