The death rate statistics belongs to the essential health parameters and it is therefore frequently analysed. Authors suggest reviewing problems, which could be met, and discussing statistical methods in order to make the comparison and analysis of the development as much corresponding to the actual health state of the population as possible. Authors also discuss methods of the "International classification of diseases" and describe methods of direct data standardisation, including estimation of the variability. Using respiratory diseases as an example, authors illustrate the problems of revision of the code system in the "International classification of diseases" and the give examples of numerical evaluation.