This study examined the correlates of mothers' and fathers' knowledge about the daily experiences of their firstborn (M = 10.9 years) and secondborn (M = 8.3 years) children in 198 nondivorced, predominantly dual-earner families. Results revealed between- and within-family differences in knowledge as a function of mothers' work involvement, sibship composition (i.e., sex, birth order), children's personal qualities (e.g., temperament), and parents' personal qualities (e.g., education, gender role attitudes). Mothers' knowledge did not vary as a function of how much they worked outside the home, but fathers knew more about their children's activities, whereabouts, and companions when their wives worked longer hours. Parents knew more about their younger than their older offspring. Both mothers and fathers knew more about offspring of the same sex than about opposite-sex children, leading to greater within-family differences in families with mixed-sex siblings. Perhaps because parental involvement and monitoring are more “scripted” for mothers than fathers, fathers' knowledge was more consistently related to their children's characteristics than was mothers.'