Describing the course of a short-term supportive-expressive psychotherapy of a male patient with terminal cancer, this study aimed to illustrate the clinical presentation of avoidant attachment behavior and to identify potential challenges in treating these patients from a psychoanalytic perspective. We analyzed eight therapy sessions, recorded and transcribed as part of a randomized controlled trial, following the explication technique of qualitative content analysis. We analyzed a patient with high attachment avoidance as assessed by the Experiences in Close Relationships Scale measuring adult attachment. We found that ‘attachment avoidance’ subsumed different defense mechanisms, which helped the patient to reduce his fear associated with (1) feelings of dependency: denial, (2) overwhelming distress: isolation of affect, displacement, (3) feelings of guilt and shame: repression, (4) regulating his interpersonal relationships: projective identification. Adding psychoanalytic interpretations to the existing material helped to identify rigid defense mechanisms interfering with sharing his fears about death and dying. Still, the low intensity setting offered him a reliable and tolerable therapeutic relationship. Contributing to the understanding of the specific challenges in treating avoidant patients, our findings underline the importance and feasibility of establishing a holding environment and fostering a positive transference relationship to engage in a joint mourning process.