An approach to analysing data for spatial clustering is outlined, with special reference to environmental epidemiology. The method is based on recent developments in spatial point-process modelling; specifically, on the use of so-called 'second-order' analysis of bivariate point patterns. This continuous-space approach offers some advantages over analytical methods that aggregate health events to areal units. The method is implemented within the framework of a proprietary geographical information system, ARC/INFO, and is illustrated with reference to health data from a questionnaire survey of children in Preston (Lancashire). The nature of the data gained from the questionnaire means that variables which may affect the health of the children studied can be accounted for within the analysis.