Using Ecological Systems Theory and stage sequential modelling procedures for detecting mediation, this study examined how early developmental contexts impact preschoolers' performances on a measure of sustained attention and impulse control. Data from 1273 European-American and African-American participants in the NICHD Study of Early Child Care were used to identify the potential mediators of the relation between early household income-to-need (INR) and 54-month impulsivity and inattention. Exploratory analyses were also conducted to determine whether the relationships between early income, home environment, parenting stress, and the outcome variables differ for African-American versus European-American-American children. We found modest support for the study hypothesis that 36-month home environment quality mediated the INR/attention relationship. INR accounted for more home environment score variance and home environment accounted for more Impulsivity score variance for African-American children. Home environments were related to inattention in the European-American, but not African-American, group. (Contains 8 tables.)