Recent trends in marriage and fertility have increased the number of adults having children by more than 1 partner, a phenomenon that we refer to as multipartnered fertility. This article uses data from the Fragile Families and Child Wellbeing Study to examine the prevalence and correlates of multipartnered fertility among urban parents of a recent birth cohort (N = 4,300). We find that unmarried parents are much more likely to have had a child by a previous partner than married parents. Also, race/ethnicity is strongly associated with multipartnered fertility, as is mothers' young age at first birth, and fathers' history of incarceration. To the extent that childrearing across households diminishes parental resources, multipartnered fertility has important consequences for children's well-being.