Two-thirds of Irish people have not made a will, charity campaigners have warned.
In a renewed drive to get people to consider leaving a gift to a good cause, the MyLegacy organisation said only about 10% of people with a will have left a donation.
The 80 charities in the group said that about 26 million euro is left to good causes every year following a death.
Susan O'Dwyer, chairwoman of MyLegacy and chief executive of the Make-A-Wish Foundation, said the idea is in its infancy in Ireland.
"Many people just don't realise that they can give money to charities in this way," he said.
"However, the reality is that after looking after friends and family, a small share of whatever is left can make a long-lasting difference to charities and the invaluable work they do."
The group has put together the Best Will In The World Week with solicitors offering low cost consultations.
In 2011 Ireland was ranked as the second most charitable country in the world, with 75% of the population giving money to charity every month.
But the group warned that only 34% of adults have made a will and just 10%-12% of those included a gift to charity.
It said 82% of over-65s have made a will, half of 45 to 64-year-olds, and a quarter of 35 to 44-year-olds.