Objectives: The study aimed to assess the extent of knowledge of the Mental Capacity Act (MCA) (2005) among new recruits to a National Health Service (NHS) Trust. Design: Respondents were assessed before and after a brief training experience. Setting: Data were collected while respondents attended their mandatory Trust induction training. Main outcome measure: Assessment was by means of a 16-item true-false questionnaire. Results: While respondents' knowledge appeared reasonably good for some important features of the MCA, these results may have been exaggerated by a strong tendency to respond 'true', which persisted despite instructions intended to counteract it. Some significant areas of ignorance were also identified. Scores showed a small but significant improvement when participants were reassessed following a 10-minute talk on the MCA; the improvements were specific to certain items that were included in the training presentation. There were no significant differences in performance between non-clinical staff, naive clinicians and clinicians who reported having previously received training on the MCA. Conclusions: Knowledge of the MCA among newly appointed NHS staff is patchy, with some strengths but also significant weaknesses. The results demonstrate a benefit of the brief training experience, but also question how much information is retained by participants in MCA training.