A study by Christian Research found that only 45% of Christians have put a legacy gift in their will.
This week churches across the country will mark Christian Legacy Week and encourage believers to discuss death and what should happen to their assets.
The research also found the main recipients of gifts were the church (66%) and organisations focused on sharing the Gospel (50%).
It also discovered that just 5% of Christians saw legacy giving as an important way they could do this and help impact future generations.
Paul Chenery, from Christian charity TLG, which is part of the Christian Legacy consortium, said: "Legacy gifts play such an important role in ensuring the fantastic work of charities and churches continues. However many Christians have never considered leaving a gift in their will.
"Death and legacy gifts should not be a taboo subject for Christians. That's why this Christian Legacy Week we are excited to be raising awareness of the issue and providing resources to get Christians talking about it.
"A gift in your will can powerfully impact future generations and bring healing and hope to a broken world."
John Preston, the National Stewardship and Resources Officer at the Church of England said: "The call to Christian stewardship doesn't just apply to our church and charitable giving - we're called to be generous in all our giving throughout life and at the end of life.
"I commend Christian Legacy's efforts to raise the important opportunity to give through our wills."
