This study examined relationship factors associated with parental dysfunction among young African American and Latino couples. Parent dysfunction was defined in terms of parenting stress, child abuse potential, physically punitive behavior, and paternal disengagement. Fathers who reported positive relations with their own parents and partners before childbirth reported more positive adjustments to parenthood at follow-up. The quality of the prebirth partner relationship buffered the impact of a relationship breakup on a young father's adjustment to parenthood. The quality of a mother's relationship with her parents was the best predictor of her adjustment to parenthood. However, mothers who reported large declines in the quality of the partner relationship also reported high levels of parenting stress. Clinical and policy implications of findings are discussed.