Most of the documentation of possible causal links between periodontitis and atherosclerosis-related diseases appears indirect or circumstantial. There is, however, an increasing number of both experimental and longitudinal epidemiological studies which seem to support a causal relationship. A critical evaluation of the epidemiological data available might therefore be appropriate. The present study is based on a literature search using Ovid medical data base covering the period from 1989 to October 2000 and applying specific inclusion criteria. Based on a critical evaluation of the 14 investigations selected from a total of 21 retrieved from the search, a causal relationship between periodontitis and atherosclerosis-related diseases appeared possible. However, the nature both of periodontitis and atherosclerosis is multifactorial, and caution should be exercised when implicating periodontal disease in the causation of atherosclerotic disorders.