Infantile hypertrophic pyloric stenosis (IHPS) is a disease in infants caused by smooth muscle hypertrophy in the pylorus, which can progress to complete obstruction of the gastric outlet, leading to severe non-bilious vomiting. The presentation of the disease is in the form of projectile and non-bilious vomiting following feeding in infants. The etiology is unknown. In cases where diagnosis and treatment are delayed, weight loss, malnutrition, fluid and electrolyte disorders, dehydration, acid-base imbalances and even death may occur. Early diagnosis may be life saving in IHPS. Physical examination and imaging methods are used in the diagnosis. The ‘olive sign’ can be seen in most cases with IHPS. A family physician should be able to diagnose and regulate the treatment of uncommon diseases like IHPS in primary care. In this case, the palpated olive sign played a key role in the diagnosis.