Abstract In epidemiological research the calculation of appropriate measures of disease frequency is the basis for a comparison of populations and, therefore, the identification of disease determinants. Two frequencies being compared can be combined into a single summary parameter that estimates the association between an exposure and a disease. This can be accomplished by calculating either the ratio of the measures of disease frequency for two populations which indicates how much more likely one population is to develop a disease than another, or the difference between the frequencies which indicates how much greater the frequency of a disease is in one population compared with the other. In epidemiology we often need to compute measures of disease frequency mentioned above. We can do that by means of complex statistical software, but sometimes it is not easy or possible to use this software for an analysis of epidemiological data. At the EuroMISE Center of Charles University and Academy of Sciences in the framework of the research supported from grant COPERNICUS JRP-10053 the E.T. program (Epidemiology Tools) was developed. This program can be used for practical analysis of data from retrospective (case-control) studies or prospective (cohort) studies and for standardization. However, the program can be also a useful teaching tool in the epidemiology courses.