Primary care providers often struggle to identify depression, with patients with multiple chronic conditions presenting additional unique challenges. Whilst the diagnosis and treatment of depression has been explored in a range of contexts in the literature, there is a paucity of information on the impact of multimorbidity on general practitioners (GPs) attempting to diagnose and manage depression in primary care. Eight GPs with multiple referrals to a multidisciplinary clinic engaged in a semi-structured interview to discuss the impact of multimorbidity on the diagnosis and detection of depression. Interviews were transcribed and thematic analysis was used to identify key themes. Grounded theory was generated from data relating to the role of multimorbidity. Participants described multimorbidity as obscuring symptom causation, but also creating time to investigate causation and negotiate the depression diagnosis with the patient, and generating relationship through frequent presentations. Knowledge of the patient impacted on intervention recommendations, and trust facilitated patient receptivity. Treatment was affected by a range of variables, and included medical and social interventions. GP process for multimorbid patients is similar to that of patients with chronic illness. Further research is needed to know whether different processes or diagnostic categories are warranted where multiple chronic illnesses are present. Also, GPs recommend social interventions where medical interventions are perceived as inappropriate. Research into the efficacy of social interventions in multimorbid patients is needed.