This review aims to consider evidence for the impact of maternal psychopathology on the child's attachment to the mother, and the role of this in mediating the known transmission of developmental and clinical risk to children. The studies reviewed focus on mothers with depression and psychotic disorder. A number of studies (mainly of mothers with depression) demonstrate an association between insecure/disorganised infant attachments and severe maternal psychopathology, whether chronic or current, in the presence of comorbid disorder, maternal insecure or unresolved attachment state of mind, trauma/loss, or low parenting sensitivity. Whether such effects last into middle childhood, however, is unclear. Our understanding of the role of attachment in determining developmental trajectories in this group is at an early stage. Some evidence suggests that attachment may have a role in mediating the intergenerational transmission of internalising and other problems in this group, although the presence of co-occurring contextual risk factors may account for the variability in findings. A multifactorial longitudinal approach is needed to elucidate such factors. However, the current literature highlights which subgroups are likely to be vulnerable and provides an evidence-based rationale for taking an attachment-based approach to intervention in this group. © 2009 Springer Verlag.