Aims Heart failure (HF) remains a major public health challenge worldwide. Contemporary epidemiological data on HF hospitalization rates and related in-hospital mortality are scarce also in Poland. The aim of the study was to determine the trends in hospitalization rates due to HF and related in-hospital mortality in Poland in the recent decade. Methods and results Data on HF hospitalizations and in-hospital mortality in patients aged >17 years in Poland between 2010 and 2019 were obtained from the central database of the Polish National Health Fund. Hospitalizations with either primary or secondary diagnosis of HF were identified using the 10th revision of the International Statistical Classification of Diseases and Related Health Problems codes (I50, I42, J81 with extensions, and R57.0). There were 4 259 698 HF hospitalizations and 608 577 in-hospital deaths (14% in-hospital mortality) reported during 2010-2019 in Poland. During this period, there was a steady increase in the number of HF hospitalizations per 1000 inhabitants in subsequent years, being more pronounced in men than in women (in 2019: 16 and 13 HF hospitalizations per 1000 inhabitants in men and women, respectively). The relative risk of HF hospitalization was higher in men than in women, and this gender-related difference steadily increased from 9% in 2010 to 25% in 2019. During 2010-2019, there was an increase in the number of HF hospitalizations per 1000 inhabitants in subsequent age groups, with a trend being more pronounced in men than in women (129 and 99 HF hospitalizations per 1000 inhabitants in men and women aged ≥80 years, respectively). During this period, there was a slight increase in in-hospital mortality during HF hospitalization in subsequent years, being more pronounced in women than in men (in 2019: 16% and 14% of in-hospital mortality in women and men, respectively). The relative risk of in-hospital mortality during HF hospitalization was higher in women than in men, and this gender-related difference steadily increased from 8% in 2010 to 18% in 2019. During this period, in-hospital mortality during HF hospitalization was~12% for women and men aged 18-29 years, whereas the highest values of in-hospital mortality reached~19% for patients aged ≥80 years. Conclusions We have observed steady growing trends in HF hospitalization rates and related in-hospital mortality in Poland over the last decade. Both age and gender have differentiated the reported epidemiological patterns.