Abstract: Described as the most common cause of gastric outlet obstruction and the most common surgical cause of vomiting in infants, Hypertrophic Pyloric Stenosis (HPS) is defined as a hyperplasia of smooth muscle fibers of the pylorus that is responsible for the narrowing of the pyloric canal and obstruction of gastric emptying. It occurs at a rate of 1–4 per 1000 live births with a male to female ratio 4:1. The classic presentation of HPS is nonbilious, projectile vomiting in a full-term neonate with a classic presentation at 3 to 4 weeks of age. We report in here a delayed presentation of HPS in an infant aged 4 months who presented with projectile nonbilious recurrent episodes of post prandial vomiting, where history, examination and investigations supported the diagnosis of HPS and Ramstedt's pyloromyotomy was curative.