This chapter describes the use of disease clustering methods using diarrheal disease data from a rural area of Bangladesh for which the authors created a household-level GIS database. Understanding distributions of diseases in space and time can be useful for etiologic research and socio-environmental risk factor identification. Disease clustering techniques are not only useful as etiological research tools for chronic diseases but also for infectious diseases. The magnitude of clustering in different areas can assist with the generation of hypotheses about the underlying socio-environmental causes of the clusters. Once clusters are identified, studies can then focus on the socio-environmental characteristics of the areas where clusters are found.