BACKGROUND: Severe soft tissue infections are surgical emergencies typically accompanied by sepsis. Early recognition and management optimizes patient outcomes. Single-centered studies on these infections are limited due to their rare incidence. MATERIALS & METHODS: We propose a protocol for the SENSEI (Severe Necrotizing Soft Tissue Infections) study, a multi-centered audit across the United Kingdom to assess current clinical practice for treating severe soft tissue infections in adult and paediatric populations. This will be compared with standards predetermined by the Surviving Sepsis Campaign and Sepsis 6. This audit will follow a trainee collaborative model, where doctors in surgery and ICU are invited to participate by the Reconstructive Surgery Trials Network and Paediatric Critical Care Society Audit Network. Each site will have a local lead, and at least one collaborator each from surgical and intensive care teams. Data collected will include presentation, investigations, and management of severe soft tissue infections. ETHICS & DISSEMINATION: As the SENSEI study is an audit and not research, approval is not required from a NHS research ethics committee. Findings of the study will be reported in scientific meetings and peer-reviewed journals.