‘Electronic Monitoring’ (EM) uses devices to monitor individuals’ whereabouts. In 2010, South London and Maudsley medium secure unit introduced EM to monitor individuals on leave. Analysis after two years revealed EM was associated with increased unescorted leave and reduced leave violation; however, comparative costs were not established. This study aims to compare costs of EM for patients on leave by comparing average total cost per patient with and without EM. Costs were compared before and after implementation of EM. Total cost of leave for each group was divided by number of patients to generate average total cost per patient. The average total cost per patient without EM was £1702; £1617 with EM. Although cost decreased, this was not statistically significant. The results showed no significant difference between average total costs per patient before and after EM. The finding of EM being cost-neutral is cautiously optimistic. Further trials are recommended. Login using your SSSFT NHS OpenAthens for full text. SSOTP - You can request a copy of this article by replying to this email. Please ensure you are clear which article you are requesting.