People with severe mental illness (SMI) experience significant health inequalities, and their physical health needs are often not addressed. This article describes the development and implementation of a physical health passport, known as My Physical Achievement Log (My PAL), which aims to improve physical health monitoring in people with SMI. The article explains how a literature search and information from official reports were used to identify physical health indicators and to devise a system for recording these. It also describes how feedback was obtained from mental health nurses to improve the My PAL tool and pilot it in mental health services. Further research to evaluate service users’ experiences of using the My PAL tool is being undertaken to enhance its usability.