Acute appendicitis is one of the most common surgical emergencies with a life time prevalence of approximately 1 in 7. Surgery for acute appendicitis is the most frequent operation performed (10% of all emergency abdominal operations). There are two groups of inflammation, obstructive and catarrhal. Catarrhal appendicitis is mostly observed in children obstructive appendicitis. When the appendix becomes obstructed usually observed in adults, the process of events begins with accumulation of normal mucous secretion, proceeds to proliferation of the contained bacteria and pressure atrophy of mucosa. Detailed history and physical examination forms the corner stones of the diagnosis of acute appendicitis. There is no other common situation where clinical features, accurate diagnosis, and immediate decision are of such important. Its use has increased lately and it is becoming an investigation of choice in doubtful cases and in female population where gynecological causes need to be ruled out. Helical CT has proven to be an effective and accurate means of diagnosing acute appendicitis with reported sensitivities of 90–100%, specificities of 91–99%, accuracies of 94–98%, positive predictive values of 92–98%, and negative predictive values of 95–100%. The role of diagnostic laparoscopy is limited to two groups of patients: (1) pre-menopausal women, in whom the differential diagnosis with gynecologic conditions can be difficult, and (2) obese patients. Proper history and detailed clinical examination will results in three sets of clinical situations: 1. diagnosis of acute appendicitis, 2. suspected acute appendicitis, and 3. pain right iliac less likely to acute appendicitis. Current standard treatment of acute appendicitis is appendicectomy.