The importance of legacies to Jewish charities will be highlighted during a "Legacy Shabbat" next month being supported by the United, Reform and Liberal movements.
In services on March 1, shuls will focus on the issue either through rabbis' sermons or leaflets and other promotional material.
The initiative has been arranged through Jewish Legacy, representing 47 charities from Ajex to Jewish Women's Aid.
Executive manager Gina Ross said: "If we don't leave legacies to carry on supporting our charities, more and more of them are going to have to close.
"I think a lot of people are not aware of legacy giving. We want to get the message out."
Though 80 per cent of the community give to charity during their lifetime, far fewer leave money from their estate - around one-in-four according to Ms Ross.
Jewish Legacy chair Nigel Ross pointed out that a legacy gift was "particularly suited to someone whose finances prevent them from giving while they are alive, because it runs no risk of prejudicing their living standards".
Reform Judaism development director Adam Overlander-Kaye said the movement relied on legacy giving as an essential funding source.
"If we are to continue growing and doing the programmes we do, we're going to be looking for legacy gifts. It is essentially a gift to ensure the vibrancy of the movement for the future."
His sentiments were echoed by Jewish Care fundraising director Daniel Carmel-Brown, who said: "As a founding member of the Jewish Legacy campaign, we're actively supporting every effort to raise awareness of the need to remember Jewish charities when contemplating one's legacy.
"If the community wants to have organisations like Jewish Care in the future, this is one very practical and important way to help."