The aim of the study was to evaluate the population mortality seasonal dynamics in the settings of emergency medical care availability. The study was conducted in Sumgait based on the medical certificates of death data analysis for 2013. The average daily number of deaths from all causes and from circulatory system diseases, the monthly number of death cases proportion in the structure of annual death cases, the proportion of deaths from circulatory system diseases among the total number of deaths were calculated. The average daily number of deaths from all causes was 4.42, including 2.72 cases - from circulatory system diseases. The average daily number of death cases from all causes below the annual average rate was observed in June, July, August and September, and when performing the seasonal analysis - in summer and autumn from circulatory system diseases - in January, June, September and December. The winter and spring increase in all-cause mortality rate was registered, whereas the mortality rate peak was characteristic for February and March. In the seasonality analysis the largest proportion of death cases number from circulatory system diseases in the structure of total annual mortality rate was in the spring. The proportion of deaths from circulatory diseases among the death causes of Sumgait population was 61.5±1.2%. In winter, the proportion of deaths from circulatory system diseases in the structure of causes of death from all causes was minimal (53.3±2.3%), and in the summer - the maximum (68.9±2.4%). The regularity of mortality seasonal dynamics in Sumgait is the winter-spring increase and summer decrease in all-cause mortality rate; distinctive feature of the mortality seasonal dynamics in Sumgait is associated with mortality risk increase in spring due to circulatory system diseases.