This article presents findings from a study of a clinical pathway for normal labour (Normal Labour Pathway) implemented in Wales, UK. The study was conducted between 2004 and 2006. The pathway aimed to support normal childbirth and reduce unnecessary childbirth interventions by promoting midwife‐led care. This article focuses on how the pathway influenced the inter‐professional relationships and boundaries between midwives and doctors. Data are drawn from semi‐participant observation, focus groups and semi‐structured interviews with 41 midwives, and semi‐structured interviews with five midwifery managers and six doctors, working in two research sites. Whereas some studies have shown how clinical pathways may act as ‘boundary objects’, dissolving professional boundaries, promoting interdisciplinary care and de‐differentiating professional identities, the ‘normal labour pathway’ was employed by midwives as an object of demarcation, which legitimised a midwifery model of care, clarified professional boundaries and accentuated differences in professional identities and approaches to childbirth. The pathway represented key characteristics of a professional project: achieving occupational autonomy and closure. Stricter delineation of the boundary between midwifery and obstetric work increased the confidence and professional visibility of midwives but left doctors feeling excluded and undervalued, and paradoxically reduced the scope of midwifery practice through redefining what counted as normal.