This study examined the relationships between instrumental activities of daily living (IADL) skills and a range of demographic, medical, neuropsychological and psychological variables in patients following coronary artery bypass graft (CABG) surgery. Participants (N = 111; 92 males, 19 females; 111 white British or Irish ethnicity) completed a battery of demographic and medical questionnaires, and standardised neuropsychological, psychological and functional assessments in a within-subjects, cross-sectional design. Correlational analyses identified significant relationships between three covariates (current smoking, anxiety and depression) and IADL functioning. Subsequent logistic regression analysis revealed that only post-operative depression independently predicted IADL functioning. It is important that clinicians recognise the bi-directional nature of the relationship between depression and IADL functioning as evidenced in this study, and ensure that these factors are addressed in the assessment and treatment of CABG patients in order to maximise surgical benefits. It is hoped that future research will build upon the finding of this study to increase our understanding of the impact of depression on IADL functioning, and to develop effective methods of intervention for at-risk individuals.