The development of visual attention is a key component of cognitive functioning in infancy and childhood. By the time children in poverty reach school, deficits in attention are readily apparent; however, when these attention delays manifest is unknown. The current study tested attention longitudinally at 6, 9 and 12?months in infants from high-socio-economic status (SES) and low-SES families. Infants were tested in a free play attention task in both simple and complex conditions, and two measures each of attention and inattention were scored. High-SES infants showed greater attention overall and greater increases in attention when the stimuli were more complex. Low-SES infants showed higher inattention than their high-SES peers at all ages and were less likely to modulate their attention on the basis of stimulus complexity. Thus, by 6?months of age, low-income infants already show deficits in attention. Results are discussed in terms of adaptability, implications for social development and attention interventions.