Background. Though early features of infant cognition are predictive of executive function (EF) in typically developing (TD) children, there is little information regarding the developmental origins of EF in neurogenetic conditions, such as Down syndrome (DS). Methods. The current study compared the performance of infants with and without DS on four dimensions that are hypothesized EF precursors: attention shifting, sustained attention, processing speed, and action planning. The relationship between these EF precursors at Time 1 and EF performance at Time 2 (6 months later) was also examined in the DS group. Participants were 58 infants with DS, M chronological age = 11.32 months, SD = 3.50; M developmental age = 7.93 months, SD = 2.79, and 40 TD infants, M chronological age = 8.14, SD = 3.25; M developmental age = 8.18 months, SD = 3.51. Results. Results showed that infants with DS shifted their attention more slowly, looked at objects for longer durations, and demonstrated a longer latency to contact objects when compared to TD infants at Time 1. Attention shifting at Time 1 significantly predicted EF performance at Time 2 in the DS group. Conclusions. This study provides evidence that an early atypical presentation of EF precursors is detectable during infancy in DS and is predictive of subsequent EF performance. These findings contribute to the identification of areas of early cognitive risk in DS and can inform future interventions in this population. Infant Precursors of Executive Function in Down Syndrome Background Down syndrome (DS) is the most common chromosomal cause of intellectual disability and affects approximately 1 in every 691 live births in the United States per year (Parker et al., 2010). Individuals with DS are predisposed to a specific phenotypic profile that includes relative competencies in visual processing, receptive language, and nonverbal social functioning, and relative challenges in motor skills, expressive language, and auditory processing (Daunhauer & Fidler, 2011). In addition to general cognitive delays present throughout the lifespan in DS, there is growing evidence of specific challenges in the 'executive functions' (EFs) required for goal