The design of buildings, particularly interior design, is acknowledged to have an effect on those who live and work there. Within the context of health care, a number of studies have attempted to identify what works best and least well. The outcomes measured include clinical outcomes, and patient and staff wellbeing. However to date there has been limited research examining the role of design in maternity units. This paper provides the background to a three-year multi-method/multisite study examining the impact of maternity unit design on satisfaction levels, and of staff perceptions of work performance. Results are given in three accompanying papers. This article provides details of the participants: women who had recently given birth (n=559), and staff (n=227) working within the units. Methods included questionnaire survey, focus group, individual interview and on-site design evaluation.