Entries for the 2020 Dublin City Marathon will be decided on a lottery system instead of the traditional first-come, first-served online process.
Marathon bosses say the decision has been made due to increased demand for race entries.
An additional 2,500 places were made available for this year's race - but it still didn't meet demand.
More than 22,000 runners competed in Sunday's Dublin Marathon, which was celebrating its 40th year.
Race director Jim Aughney said: "Many races that have more interested runners than they can accommodate have moved to a lottery registration system in recent years.
"Demand for the Dublin Marathon has never been greater, and we believe the lottery is the fairest system to offer all runners the same opportunity to participate."
Entries will open from November 1 to November 30 and successful registrants will learn their entry status via SMS and email between January 3 and January 10.
Those successful will have until January 31 to redeem the offer.
