BACKGROUND A decrease in cardiovascular mortality rates, including deaths due to ischaemic heart disease (IHD), has been observed in Poland since mid-1990s, and at the same time a rapid increase in sudden cardiovascular death (SCD) rate was noted. OBJECTIVE To evaluate changes in mortality due to SCD, IHD and SCD+IHD that occurred in 2003-2008 in the Polish population aged 25-64 years. METHODS Individual data from death certificates and demographic data were obtained from the Central Statistical Office and all analyses were performed in the Department of Cardiovascular Disease Epidemiology, Prevention and Health Promotion. SCD was defined as codes I46.1 and R96, and IHD as codes I20-I25 according to the Tenth Revision of the International Classification of Diseases (ICD-10). Calculated mortality rates per 100,000 inhabitants for 5-year age groups were standardised for the European population structure. RESULTS In 1997-2008, premature mortality due to SCD among adult men and women aged 25-64 years showed only small variations until 2003, and later an upward trend was observed. In 2005-2008, mortality due to SCD increased by 40% among men and 45% among women, but total mortality due to SCD+IHD remained stable. There was no marked variation in the proportion of mortality due to IHD+SCD in total cardiovascular disease (CVD) mortality both in men and in women. The rate of SCD was related to age. A notable finding was the equalisation of mortality rates due to IHD+SCD per 100,000 in nearly all age groups except for the oldest men and women. In the whole adult Polish population, no clear difference in standardised mortality rates could be noted between 2003 and 2008. SCD mortality rate and its proportion in total CVD mortality differed significantly in relation to the region of Poland. SCD mortality rate among men in the Lubusz and Lesser Poland voivodeships decreased by more than 25% (in women only in the Lubusz voivodeship). In the remaining voivodeships, increases in SCD mortality rate were observed (among men, by 171% in the Pomeranian voivodeship, 66% in the Świętokrzyskie voivodeship, and 60% in the Opole voivodeship; among women, by 248% in the Pomeranian voivodeship, 88% in the Silesian voivodeship, and 85% in the Opole voivodeship). No differences in mortality rates due to IHD+SCD in relation to the region of Poland were observed. CONCLUSIONS IHD mortality rates in the Polish population aged 25-64 years were underestimated in the majority of voivodeships. At the same time, SCD mortality rates were overestimated. These results indicate deficiencies in our medical care system regarding the diagnosis and prevention of sudden deaths, and awareness of symptoms of life-threatening conditions.