Family interaction during pregnancy and the transition to parenthood creates the social environment in which the fetus becomes part of the family, family relationships and roles are reorganized, and the infant's temperament appears. The purpose of this study was to examine the relationships among family dynamics, parental-fetal attachment, and infant temperament across the transition to parenthood. A sample of 91 families in Helsingborg, Sweden completed the Family Dynamics Measure and the Maternal/Paternal Fetal Attachment Scale during the third trimester of pregnancy. When the infant was 8-9 months old, mothers (n = 62) and fathers (n = 54) again completed the Family Dynamics Measure. The mother completed the Revised Infant Temperament Questionnaire as well. Overall, we found small changes in family dynamics, with an increase in perceived role conflict and mutuality reported by mothers. Fathers reported greater fetal attachment than their partners. Greater paternal- and maternal fetal attachment was related to more positive family dynamics, and maternal-fetal attachment was positively related to infant mood at 8 months. The stability of family dynamics across the transition to parenthood is a sign that most families negotiate this transition without difficulty.