The VenUS II trial is the first large, prospective clinical study to investigate the effect of larval therapy and hydrogel on both the bacteriology and healing of leg ulcers. This trial will compare the clinical and cost effectiveness of two types of larval therapy (loose and bagged) with a standard debridement intervention (hydrogel) in terms of effects on time to complete healing, time to debridement, wound microbiology, cost of treatment and health-related quality of life. This paper describes the aims and design of the trial, outlines the eligibility criteria for patients and discusses the nurses' role in the study. This article has not been subject to peer review.