The aim of the study was to assess trends in overall mortality and the impact of the major causes of death to the overall mortality changes during the different periods of 1990-2000. Data about the population and the deceased was obtained from Lithuanian Department of Statistics. Mortality rates were age-standardized. Coefficient of logarithmic regression was used for the assessment of the trends in mortality. The impact of the major causes of death to the changes in overall mortality was estimated applying the methodology of I.M. Joung (1996). Trends in mortality of Lithuanian population were not uniform throughout the period of 1990-2000. The average increase in mortality during the period of 1991-1994 reached 4.1% per year, while in 1995-2000 similar decreasing trend was observed. Statistically significant increase was noted only in the age group of 20-64, while the decline was characteristic for all other age groups. Mortality of young population was decreasing more significantly. Negative changes in mortality during the period of 1990-1994 were mainly determined by external causes of death (45.1% in males and 28.3% in females), and positive changes that occurred in 1995-2000 were determined by mortality from cardiovascular diseases (nearly 50%). The impact of cancer and respiratory diseases was significant neither for negative, nor positive changes in overall mortality.