The accident occurred this morning when the truck landed on a group of cyclists who were out training for a sports event.
The regional government said emergency services in the region of Navarra mobilised a helicopter, three ambulances and three fire trucks to the site.
The two cyclists died instantly and the stretch of road where the incident happened at Caparroso, 330 kilometres northeast of Madrid, was closed to traffic.
Police are still investigating the cause of the accident.