While psychological distress in cancer patients is common, little is known about how general practitioners (GPs) assess distress. Using semi-structured interviews, a phenomenological study of seven GPs was conducted to explore GPs' experiences of assessing distress. Findings revealed five themes: (1) Being in the Relay Team - receiving and passing the baton: where the assessment of distress was conceptualised as a relay baton passed between a team of health care professionals, with GPs most involved at diagnosis and in the palliative phase. (2) Being in a Relationship: where the doctor-patient relationship was described as a powerful facilitator to assessment. (3) Being Skilled: where GPs perceive they are skilled at assessment adopting a patient-centred approach. (4) Being Challenged - encountering barriers: challenges with assessment were identified regarding the GPs' own emotions, patient related factors and time; the duality of family as both barrier and facilitator was voiced. (5) The Intruder in the Room: where GPs did not use validated screening tools which were viewed as an intruder in the doctor-patient relationship. Further research to objectively assess GPs' skills in distress assessment and attitudes towards the use of screening tools within the cancer care context are merited.