Background: This study provides an exploration of factors implicated in the intergenerational cycle of child maltreatment. Families with newborns where at least one of the parents was physically and/or sexually abused as a child (AP families) were compared in terms of risk factors to families where the parents had no childhood history of victimisation (NAP families). The mediational properties of risk factors in the intergenerational cycle of maltreatment were then explored. Methods: Information was collected by community nurses as a part of the "health visiting" service. Data was collated across 4351 families, of which 135 (3.1%) had a parent who self-reported a history of abuse in childhood. The health visitor visited each family at home when the child was 4 to 6 weeks of age to assess the presence of risk factors. Results: Within 13 months after birth, 9 (6.7%) AP families were referred for maltreating their own child in comparison to 18 (0.4%) NAP families. Assessments found a significantly higher number of risk factors for AP families. Mediational analysis demonstrated that the presence of three significant risk factors (parenting under 21 years, history of mental illness or depression, residing with a violent adult) provided partial mediation of the intergenerational continuity of child maltreatment, explaining 53% of the total effect. Conclusion: Prevention may be possible, once a history of parental childhood abuse has been identified, by offering services in priority to those families where a parent is under 21 years, has a history of mental illness/depression and/or there is a violent adult residing in the household. However, it must also be acknowledged that these factors do not provide a full causal account of the intergenerational transmission and consideration should be given to additional factors, such as parenting styles (see Part II of this mediational model, Dixon, Hamilton-Giachritsis, and Browne, 2004).