Background: Disease-specific patient-based questionnaires are being used increasingly to evaluate treatment outcomes in coronary heart disease (CHD) from the patient's perspective. However, most have been developed to evaluate health-related quality of life (HRQoL) in medically rather than surgically treated patients and many have not been rigorously evaluated against required standards. There are currently no validated questionnaires to measure patient- based outcomes after coronary revascularisation, the surgical treatment for CHD. Objectives: To develop a new patient-based instrument, the Coronary Revascularisation Outcome Questionnaire (CROQ), to measure health outcomes and HRQoL before and after coronary artery bypass graft surgery (CABG) and percutaneous transluminal coronary angioplasty (PTCA). To evaluate the psychometric properties of the CROQ using classical psychometric methods. Design: Psychometric study. Subjects: A total of 725 (79% male) patients undergoing CABG and 643 (71% male) patients undergoing PTCA at three hospitals in the UK. Methods: Qualitative methods (literature review, review of existing instruments, patient interviews, and expert opinion) were used to develop two versions of the eROQ (CROQ-CABG and CROQ-PTCA). Two field tests were then conducted by postal survey to patients before and 3-months after revascularisation firstly, to identify possible items for elimination (item reduction) and secondly, to evaluate the psychometric properties (reliability, validity, responsiveness) of the item- reduced CROa in independent samples. Results: The CROQ was acceptable to patients, satisfied tests of scaling assumptions, showed good internal consistency, test-retest reliability, validity, and responsiveness. 4 Conclusions: The CROQ is a new l psychometrically rigorous patient-based measure of outcome for coronary revascularisation. The CROQ has many potential uses in evaluative research l such as in clinical trials of effectiveness I and as a routine clinical audit tool to assist providers of CABG and PTCA in monitoring the outcomes of care