Police officers have closed off Burniston Road near the Northstead Manor Drive junction following the crash involving two cars.
An elderly man has been extracted from one of the vehicles.
North Yorkshire Fire and Rescue and Yorkshire Ambulance Service are also at the scene.
A spokesperson for North Yorkshire Police said: "The road is currently closed, please use an alternative route until further notice."
East Yorkshire Motor Service has tweeted that there has been a 'serious accident'. The 3/3A bus service is diverting via Columbus Ravine, Dean Road, Northstead, Cross Lane and resuming normal route near Alpamare.