John Bowlby's Attachment Theory is being increasingly operationalised in the world of developmental research, but as yet its implications for clinical work are relatively less discussed. This paper addresses the issue of the measurement of attachment patterns and how knowledge of these can inform psychoanalysts’ work with their patients. It looks at the implications of Attachment Theory at all stages of the therapeutic process, but concentrates particularly on how it can help with the crucial phase of building the working alliance.