- The concept of epidemiological transition is now quite widely recognized, if not so widely accepted. The transition appears to progress at varying speeds and to different extents spatially; it seems that there can be considerable international, regional and local variations in its progress. The paper examines this contention in the case of a number of countries in Southeast Asia, principally Hong Kong, Malaysia and Thailand. Drawing on evidence from this region, the paper highlights the importance when researching epidemiological transition of the time period under consideration; socio-cultural variations; the nature and quality of data, and spatial scale. It makes some suggestions as to the potential of the concept of epidemiological transition in health care planning and development studies.