In paediatric general surgery hypertrophic pyloric stenosis (HPS) is well-researched and documented (Dudgeon 2005, Panteli 2009). Significant medical advances have improved its diagnosis, treatment and prognosis, and there is now almost a 100 per cent success rate (Panteli 2009). However, the cause of this disease process remains poorly understood (Dudgeon 2005, Panteli 2009). This article reviews the literature on the cause and management of HPS.