The survey, which canvassed the views of 2074 adults across Great Britain, found that over half (55%) did not have a will in place at all, rising to nearly two-thirds (65%) for those with children in the household.
Surprisingly, nearly one in four (24%) of those aged 55 and over also did not have a will in place.
Of those surveyed, almost one in 10 (9%) had not reviewed their will in over 10 years and a further one in ten in the last five years.
Significant changes such as the addition of children and changes in personal wealth would likely require amendments to a will.
Significant changes to the law on intestacy came into play on 1 October 2014 in order to reduce costs and make the law easier to understand.
For married couples, including those in civil partnerships, the whole estate will now pass to the surviving spouse in all cases where there are no children or descendants. Until now, other relatives had a share of the estate.
In the case where there are surviving children, as well as a spouse or civil partner, the sharing of assets has been simplified. For example, the surviving spouse will take all personal chattels, a lump sum of £250,000 and half of any balance of the estate outright rather than, as previously, in a trust.
Vicky Day, senior associate and wills specialist at Thomas Eggar LLP, said: “The change in law has redefined the division of assets for those who pass away without a will in place.
“Whether you are married, in a civil partnership, with or without children, the changes will affect you and your relatives and we urge those without a will to address the situation