Pressure ulcers are a common and serious health care problem in all health care settings. Results from annual national pressure ulcer prevalence surveys in the Netherlands and Germany reveal large differences in prevalence rates between both countries over the past ten years, especially in nursing homes. When examining differences in prevalence and incidence rates, it is important to take into account all factors associated with the development of pressure ulcers. Numerous studies have identified patient related factors, as well as nursing related interventions as risk factors for the development of pressure ulcers. Next to these more process oriented factors, also structural factors such as staffing levels and staff quality play a role in the development of pressure ulcers. This study has been designed to investigate the incidence of pressure ulcers in nursing homes in the Netherlands and Germany and to identify patient related factors, nursing related factors and structural factors associated with pressure ulcer development. The present article describes the protocol for this study.