The company will build a full-sized store near Tesco on the new retail park between the High Street and Nant Hall Road.
Prestatyn Town Cllr Gerry Frobisher said hailed the announcement as a huge boost for the town.
He said: "Where there is a Marks and Spencer it is a boost for any town centre. I'd like to think it would really enhance Prestatyn and I think the town's independent stores will survive because they provide a different service and I think they will benefit as well.
"Some of the independent shops in the town could close but I'd like to think that they would benefit from the increased footfall."
An M&S spokespswoman said: "We are planning to open a store in Prestatyn and it will be a full store with both food and clothing ranges. It will be located on the new retail park and should open in spring 2010."
The retail park is to be built by Stadium Developments who were behind the Parc Llandudno project which opened in 2006.
Plans are underway for the park, which will feature a number of retail units, parking and landscaping to be linked with the Tesco site.
Cllr Frobisher said: "With the railway station, new school and the new Scala, Prestatyn is really on the up. It is the 21st century and we have to look like we are moving forward."
But he also warned of the dangers of big name stores failing to provide job security for local staff, he said: "I'd like to see more commitment to create permanent full-time jobs rather than lots of part-time positions. This would give more job security to local people."
Town Mayor Anne Horobin said: "I would welcome any quality development into the town and look forward to the confirmation of further additions in due course."