Aim: Appendicitis is uncommon under the age of three, with few series reported in the literature. The diagnosis has been reported to be delayed, with a perforation rate between 60-100%. The aim of this study is to delineate the presentation and outcome of appendicitis in children less than three years of age in the era of ultrasound. Methods: An investigation was carried out based on retrospective review of children under the age of three who underwent an appendicectomy over a 12-year period. Modified Pediatric Appendicitis Score (MPAS) was retrospectively applied with a score of 5 and above correlating with a high likelihood of acute appendicitis. Results: Thirty children underwent appendicectomy for acute appendicitis. The mean age was 26.4 months. Ultrasound was performed in 25 patients (83.3%) at presentation and diagnostic in 20. The remaining five patients had a high MPAS consistent with a high-likelihood of acute appendicitis. Perforation was noted in 13% of patients (n=4) and an appendicular mass was found in two patients. Ultrasound when combined with a MPAS had 100% accuracy in this population. Conclusions: In children less than three years of age ultrasound combined with the MPAS seems to be an accurate diagnostic tool in acute appendicitis, with a low incidence of perforation.