The Cabinet today agreed that a number of referendums, including one on same-sex marriage , will be held in May next year.
The polls expected to be held together are the same-sex marriage referendum and the referendum on reducing the age of candidates allowed to contest the presidential election from 35 to 21.
No specific date has been set.
The issue was discussed today by Ministers at their final meeting before Christmas.
The decision of a May date means that the Coalition is expected to have cleared a number of politically sensitive issues in April, including the first Irish Water bills and a possible spring statement on the economy.
The latest Irish Times/Ipsos MRBI poll showed support for same-sex marriage is rising steadily, with 71 per cent saying they would vote in favour of it.
However, Fine Gael and Labour figures believe the support is soft and are wary of complacency following the 2012 children's referendum.
It passed on a very small turnout after support ebbed away in the months leading up to polling day.
The Government intends that the Child and Family Relationships Bill, which provides for the adoption of children by same-sex couples, will be passed into law by the time the referendum takes place.
The Cabinet also decided today that a byelection in Carlow/Kilkenny to fill the Dail seat vacated by European Commissioner Phil Hogan is likely to be held on the same day as the referendums.