This book presents the experience from a study that investigated executive function (EF) and sustained attention (SA) in preterm and full-term infants at 8 months after expected date of delivery and at 10-11 months of age. Executive function and sustained attention emerge in infancy and continues to develop throughout childhood. Executive function and sustained attention is believed to underlie some learning problems in children at school age. Although numerous studies have reported that the overall development of preterm infants is comparable to that of full-term infants at the same corrected age, it is unclear to what extent the development of specific cognitive abilities is affected by prematurity and/or other factors such as medical complications. As preterm infants have a high rate of learning difficulties, it is possible that factors associated with prematurity specifically affect the development of some regions of the brain associated with the regulation of executive function and sustained attention. Thirty-seven preterm infants without identified disabilities, and 74 due date and gender matched healthy full-term infants, participated in the study. The preterm infants were all less than 32 weeks gestation and less than 1500 grams birth weight. The findings of the study showed that preterm infants performed significantly more poorly than full-term infants at both 8 months after the expected date of delivery and 10-11 months chronological age on all measures of executive function and sustained attention. However the difference between preterm and full-term infants at 8 months after expected date of delivery was much less than at 10-11 months chronological age. The results suggested that the effects of maturation are greater than the effects of exposure to extra uterine environmental stimuli on the development of executive function and sustained attention.