AIMS OF THE STUDY: This paper uses the findings of a recent bibliometric analysis of published UK nursing research to ask whether the field is characterized by a fundamental split between two underlying areas of research interest. These can be termed 'endogenous' and 'exogenous'. The former term describes research which tends to be concerned with problems and issues to do with nursing as a profession; the latter is concerned with problems and issues centring around the nursing of patients. DESIGN/METHODS: Papers in the Wellcome Trust's Research Outputs Database (ROD), a database of UK biomedical research, were analysed. Nursing papers published between 1988 and 1995 numbered 1,845, just less than 1% of the total papers in the ROD. RESULTS/FINDINGS: Analysis of the subfield identified that nursing research was atypical of biomedical research as a whole in a number of ways. One difference was that usually in biomedical research there is a general correlation between numbers of funders acknowledged on a paper, numbers of authors, and esteem of the journal in which a paper appears. In nursing there was, if anything, a tendency for highly esteemed papers to have fewer authors and be less likely to have acknowledged funding. However, the apparently endogenous and exogenous papers have quite different characteristics. This paper explores this apparent difference and possible reasons for this difference and will briefly compare nursing research with some other newly emerging social and academic groups. CONCLUSIONS: Thinking of nursing research outputs in this way can provide insight into the existence of different reward systems influencing nurse researchers. However, it is impossible to draw too confident a differentiation without reading each individual paper and making judgements about whether they are 'endogenous' or 'exogenous', a practice generally beyond the scope of bibliometric practice.