The literature suggests that maternal insecure attachment is a risk factor for postpartum depression which, in turn, affects motherinfant bonding. However, recent research in attachment suggests that the investigation of attachment networks provides further insight in the understanding of psychological outcomes. This study aims to test a model according to which mothers’ attachment towards each of their parents contributes to explain attachment towards their romantic partners, which itself is associated with maternal postpartum depression and, in turn, with motherinfant bonding. The Attachment Multiple Model Interview, the Edinburgh Postnatal Depression Scale, and the Postpartum Bonding Questionnaire were administered to 90 mothers of infants under 6 months of age (32 with postpartum major depression). Results showed that attachment towards the partner (1) is best explained by attachment to the father and (2) mediates the link between attachment to the father and depression severity. Also, depression severity mediates the link between attachment to the partner and motherinfant bonding. These results highlight the role of attachment models towards the romantic partner and the father in the perinatal period and the relevance of attachment-focused therapeutic programs in treating postpartum maternal depression.