This study tested predictions from economic and developmental theories that maternal time with an infant is important for mother-child relationships and children's development, using time-use diaries for mothers of 7- to 8-month-old infants from the National Institute of Child Health and Human Development Study of Early Child Care (N=1,053). Employment reduced time with infants, but mothers compensated for some work time by decreasing time in other activities. With family and maternal characteristics controlled, time with infants predicted high Home Observation for Measurement of the Environment (HOME) scores and maternal sensitivity, but bore little relation to children's engagement with mothers, secure attachment, social behavior, or cognitive performance from 15 to 36 months. Mothers who spent more time at work had higher HOME scores. Maternal time with infants may reflect maternal characteristics that affect both time allocation and maternal behavior.