This article provides an illustration of how the use of the Adult Attachment Interview (AAI; George, Kaplan, & Main, 1985) can be extended beyond the research arena to its use as a clinical instrument in parent-infant psychotherapy. The article is based on the ongoing work of the Parent-Infant Project team at the Anna Freud Centre, London, where psychoanalytically trained therapists routinely administer the AAI early in the therapeutic process. In the first part of the article, we introduce the thinking behind the use of the AAI as a clinical tool and its particular relevance to the field of parent-infant psychotherapy. In the second part, we track the accruing clinical picture built up from a case example of the initial clinical sessions with a father who attended the Parent-Infant Project with his partner and two young children, and from the father's AAI. The discussion of the AAI material illustrates the distinct, yet related, interpretations of the parent-infant psychotherapist and the independent AAI coder as each made sense of the father's interview transcript. The resulting dialogue, between the psychodynamic-clinical and the attachment-research based approaches to the AAI, aims to highlight the added value the interview provides to the clinical understanding and process in parent-infant psychotherapy, which may ultimately help bridge the gap between the research and clinical domains.