Aim: To analyse quantitative changes in patient well-being concurrent with chaplaincy interventions in a retrospective study of a group of Primary Care centres in Sandwell and West Birmingham, United Kingdom. Background: Anecdotal evidence suggests that support from trained Primary Care Chaplains may be particularly useful for those with subclinical mental health issues; it can reduce the tendency to ‘medicalise unhappiness’ and is a positive response to patients with medically unexplained symptoms. However, to date there has been no published research attempting to quantify their contribution. Method: Data were gathered from a group of Primary Care Centres, which make use of a shared Chaplaincy service. Demographic data and pre–post scores on the Warwick and Edinburgh Mental Wellbeing Scale (WEMWBS) were collected for patients who had attended consultations with a Chaplain. These were subjected to tests of statistical significance to evaluate the possible contribution of chaplaincy to patient well-being along with possible confounding variables. Findings: a substantial improvement in WEMWBS scores (mean=9 points, BCa 95% CI [7.23, 10.79], P=0.001) post-intervention. The improvement in scores was highest for those with initially lower levels of well-being. There is therefore evidence that chaplaincy interventions correlate with an improvement of holistic well-being as measured by a WEMWBS score. A prospective study on a larger scale would provide more detailed information on the interaction of possible variables. Further study is also required to evaluate the implications of this result for patient outcomes and GP resources. The efficacy of Primary Care Chaplaincy is under-researched and difficult to measure. This paper represents the first attempt to quantify a measurable improvement in the well-being of patients who are referred to the service.