Accumulating evidence suggests children enrolled in full-time child care often display afternoon elevations of the hormone cortisol, which is an indicator of stress. Recent advances in immunoassays allow for measurement of activity in the hypothalamic-pituitary-adrenal axis and the autonomic sympathetic nervous system from saliva, and measurement of both systems provides a more complete understanding of activity in the stress response system. This study is the first to examine both cortisol and alpha-amylase in children attending child care and focuses on the influences of specific indicators of classroom process quality. A diverse sample of 63 preschool children nested in 14 classrooms of varying quality participated in this study; child salivary cortisol and alpha-amylase were collected at six times over 2 days. Results indicate that children in classrooms with higher Emotional Support displayed a greater decline in cortisol from morning to afternoon. Further, children in classrooms with higher Emotional Support exhibited lower total alpha-amylase output while attending child care. Implications for professional development for early childhood teachers and measurement of classroom quality are discussed. (Contains 2 figures and 3 tables.)