The current report has been devoted to the presentation of the diagnosisand operative treatment of congenital hypertrophic pyloric stenosis in monozygotic twins. Special attentionhas been paid to a number of theories aiming to explain the aetiology and the mechanisms contributingto the development of congenital hypertrophic pyloric stenosis.

Keywords: Diseases in Twins, Humans, Hypertrophy, Infant, Male, Pyloric Stenosis, Twins, Monozygotic