BackgroundAcute appendicitis is one of the most common causes of acute abdomen in children. Late surgical intervention is often associated with increase morbidity and sometimes fatal outcome. We sought to determine the pattern of presentation of acute appendicitis, and the effect of late presentation on surgical outcome in children.MethodsThis is a retrospective descriptive study done at the paediatric surgical unit of Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife, Nigeria. The hospital records of all 180 patients (15 years and below) treated for acute appendicitis, between January 1995 and December 2012, were reviewed; only 156 patients had adequate records out of which 139 cases confirmed histologically as having appendicitis were analyzed.ResultsThere were 80 (57.6%) females and 59 (42.4%) males. The age range was 5-15years with mean (SD) age of 11.2 (±2.9) years. Most patients (64.7%) were more than 10 years old. Sixty-four (46%) patients had simple appendicitis while 75 (54%) patients had complicated appendicitis. More children with complicated appendicitis (63, 84.0%) presented after 24 hours of abdominal pain; and they had more vomiting (59, 78.7%), spent longer days on admission (57, 76.0%) and had more post- operative complications (34, 45.3%) compared with uncomplicated appendicitis (25, 39.1%; 29, 45.3%; 7, 10.9%; 1, 1.6% respectively), and this was statistically significant (p < 0.05). No mortality was recorded among these children.ConclusionLate presentation was common and was associated with longer duration of hospital stay and high morbidity. No mortality was recorded from the disease.