Congenital pyloric stenosis is rare in premature infants. This is a report of pyloric stenosis in a premature infant (35 weeks gestation) discovered on the 2nd day of life. There appears to be an association with polyhydramnios. Congenital hypertrophic pyloric stenosis should be considered in the differential diagnosis of premature infants with upper gastrointestinal symptoms. A review of the literature is included.