Geriatric epidemiology deals with the application of epidemiological techniques to the study of elderly persons. It is neither a simple replication of studies carried out in younger adults transposed to another collective nor a departure from basic principles. It is rather the integration of known methods, which should be taken systematically into account during their application to geriatric populations, in order to circumvent the specific problems involved in the study of this growing part of the population. This paper aims to provide an overview of the practical implications of the epidemiological study of the elderly. It is divided in two parts. A concise description of the demographic context underlining the topic relevance is followed by a discussion of the methodological aspects. It attempts to remind potential investigators of some important issues raised while studying older persons and also provide clinicians with criteria for assessing the quality of papers they read on this topic.