Using a nationally representative sample of 13,609 kindergarten children in 2,690 classrooms and 788 schools from the base year of the Early Childhood Longitudinal Study, Kindergarten Class of 1998-1999, along with three-level hierarchical linear models, this study investigates the impact of early literacy instruction on kindergarten children's learning, as measured by direct cognitive test scores, indirect teacher ratings of children's achievement in language and literacy, and indirect teacher ratings of children's approaches to learning. Two composite measures of phonics and integrated language arts are constructed from teachers' reports of their instructional practices. Findings show that classroom mean outcomes were significantly higher when classroom teachers reported using both integrated language arts and phonics more often. However, children with low initial performance benefited less from integrated language arts instruction, as measured by direct measures of achievement; such differential effects of instruction were not observed for teacher ratings of children's achievement and learning style. Policy implications of the findings are discussed. (Contains 9 tables, 2 figures, and 3 footnotes.)