According to Official Guinness Records,
The longest marathon hosting a radio talk show is 80 hours and 5 minutes and was achieved by Dulce Meneses (Spain), at the Canal 4 radio station in Arona, Tenerife, Spain from 25 to 28 March 2015.The attempt started on Wednesday 25 March 2015 at 8am and ended on Saturday 28 March 2015 at 4pm. The entire attempt was live on TV and internet.
For a complete list of 2015 records, please visit 2015 Guinness Records in Spain.