Abdominal laparoscopy is a widely accepted surgical procedure effective even for acute abdominal ailments. However, one major concern in using abdominal laparoscopy is missed lesions, in the past this has not been adequately explored. The aim of this retrospective study, therefore, is to evaluate cancerous lesions that are missed during emergency laparoscopic surgeries. The medical records of 2074 patients who had a laparoscopy from March 1996 to April 2006 for acute abdomen symptoms, including diagnostic laparoscopy (n = 119), laparoscopic appendectomy (n = 1336), laparoscopic duodenorrhaphy (n = 30), and laparoscopic cholecystectomy (n = 589) were reviewed. Missed cancerous lesions included cecal cancer (n = 2), sigmoid cancer (n = 1), and jejunum lymphoma (n = 1). The incidence of missed cancerous lesions in an emergency laparoscopic surgery is 0.19%, mainly due to its lower tactile sensitivity compared to the direct hand palpation and masqueraded by inflammatory process. Therefore, careful observation is recommended for post-emergency laparoscopic patients and follow-up should be performed within three months, especially for patients with intra-abdominal and/or severe inflammation status.