AIM:This paper reports a study examining midwives' perceptions of the way in which they diagnose labour. BACKGROUND:Diagnosis of active labour is often problematic. A midwifery workforce planning tool identified that up to 30% of women admitted to United Kingdom labour wards subsequently turned out not to have been in labour. There is evidence that if a woman is admitted to a labour ward in early labour, she is more likely to have some form of medical intervention. However, despite the impact of misdiagnosis, there is little research on the process of decision-making by midwives in relation to diagnosis of labour. METHODS:This was a qualitative study, employing focus group methods. Participants were a convenience sample of midwives working in a maternity unit in the North of England during 2002. They were asked to discuss their experience of admission of women in labour. Data were analysed using latent content analysis. FINDINGS:Thirteen midwives participated in one of two groups. They described using information cues, which could be separated into two categories: those arising from the woman (Physical signs, Distress and coping, Woman's expectations and Social factors) and those from the institution (Midwifery care, Organizational factors and Justifying actions). Midwives' decision-making process could be divided into two stages. The diagnostic judgement was based on the physical signs of labour: the management decision would then be made by considering the diagnostic judgement as well as cues such as how the woman was coping, her expectations and those of her family and the requirements of the institution. CONCLUSIONS:Midwives may experience more difficulty with the management decision than with the initial diagnosis. It may be that the number of inappropriate admissions to labour wards could be reduced by supporting midwives to negotiate the complex management hurdles, which accompany diagnosis of labour.