Objectives We aimed to estimate the potential population that requires palliative care, clarify the relationship between this population and the rate of ageing in Japan, and compare these trends with those of other countries.

Design We used the national death registration data and population projections for Japan to estimate the population in need of palliative care using the minimal estimate method developed by Murtagh et al. Linear regression was used to create a model of mortality using sex, age at intervals of 5 years, and each major disease classification. We calculated the future population in need of palliative care until 2040 and compared the ageing data to those of other countries.

Setting/participants All adults in Japan who died from 1980 to 2040 at intervals of 5 years.

Results The number of people who might need palliative care from 2020 to 2040 will also increase linearly from 1 059 000 to 1 405 000. The proportion of Alzheimer’s, dementia and senility of the total need for palliative care will increase to 43.4% in 2040. The correlation coefficient between the proportion of the population in need of palliative care and the rate of ageing was 0.24 in developed countries.

Conclusion In Japan, the population requiring palliative care in 2040 will be 1.5 times that in 2015. Palliative care needs to be provided urgently for people with Alzheimer’s disease, dementia and senility. The proportion of patients in need of palliative care may not change, although the number of patients requiring such gradually increases in developed countries.