We use data from the Fragile Families and Child Well-Being Study (FFCW), a birth cohort study of children in 18 medium to large U.S. cities, to examine the prevalence and determinants of spanking among infants and toddlers (at mean age 14 months). Taking advantage of the large and diverse sample in FFCW, we conduct separate analyses for children of African American (N=1,710), Hispanic (N=853), and white non-Hispanic (N=812) mothers. Overall, about 15% of children are spanked at 12 months, with this share rising to 40% by 18 months and nearly 50% for children age 20 months or older. We find that there are marked differences in the use of spanking across the three racial/ethnic groups, with children of African American mothers more likely to be spanked and at a younger age. Moreover, while some predictors of spanking are seen across all three groups, others vary. Mothers who are young, who report more parental stress, or report their child has a more difficult temperament are more likely to spank across all three groups. However, being a boy increases the risk of spanking only within African American families. First-born children are at elevated risk of spanking to at least some extent in all groups, but much more so within Hispanic families. In addition, maternal employment is associated with a greater likelihood of spanking in Hispanic families.Although spanking at these young ages is not necessarily indicative of maltreatment, it may be a marker for families who are at elevated risk of maltreatment. As such, our findings, by highlighting some risk factors that are common across groups as well as some that are more important for particular groups, may have implications for child abuse prevention.