Routinely collecting and using electronic patient-reported outcome (ePRO) data in clinical practice can improve patients' experience and outcomes, but implementing this at scale has proved challenging. As part of the Optimising routine collection of electronic patient-reported outcomes (OPT-ePRO) study, we therefore developed an intervention that aimed to facilitate the implementation of ePROs. We are conducting OPT-ePRO in the context of secondary care for people with chronic kidney disease in the UK, with three renal units participating as our study sites. Intervention design was guided by Normalisation Process Theory, and informed by published literature and qualitative research. The intervention consisted of a national infrastructure to securely collect, transfer and display ePRO data, complemented with materials and procedures to support kidney patients and renal unit staff with embedding ePROs in usual care pathways. The next step will be to bring the OPT-ePRO intervention into practice and iteratively refine it.