The paper presents the results of this study on mortality rate during the period of 1951-1985 for men and women aged 20-64. Moreover, the differences between male and female mortalities were analysed with a view of investigating the problem of excessive mortality ratio of men. In the period under study the descending and then ascending tendency of the mortality rate could be observed both in the male and female populations. Up to 1965 male mortality decreased gradually (by 35%) whereas the following years witnessed considerable rise of the level of male mortality (by 30% to 1985), which referred especially to males at the age range between 40 and 49, years. As regards the female population the mortality rate was decreasing till 1975. For the last 10 years increased female mortality has been observed, however, their dynamics is much more lower than that for the female group (by 6.2% less than for 1975). During the whole period examined i.e. 1951-1985 the excessive mortality ratio in men was found to be higher by 60.4%. High dynamics of the ratio concerned male population at lower age ranges.