The Patient Partnership in Care (PPiC) questionnaire was designed to measure the ability of health professionals to work in partnership with patients with long-term conditions (LTCs) to support and motivate self-management. It is a generic, 16-item questionnaire, contained on two sides of A4, incorporating space for two written comments. In a baseline survey, 97 clinicians gathered responses from 1,660 patients with LTCs in eight centres across the UK. The questionnaire was found to have face validity, construct validity, good internal consistency and sensitivity to change. It consists of two, unidimensional subscales covering patient-clinician partnership and the patient's confidence to manage their LTC (Cronbach's alpha 0.977 and 0.877 respectively). Health professionals who participated in three four-hour training sessions focusing on skills that support patients with self-management showed a significantly improved score in both subscales (with moderate effect sizes: -0.56 for both subscales). These health professionals administered the PPiC to their patients before and after the training. Regression analysis showed that patient confidence was strongly predicted by their partnership score. This suggests that the intervention of relevant training and reflection on the initial results of the PPiC can promote clinician skill development and increase the confidence of patients regarding self-management of LTCs.