Emergency services were called to a serious accident on the A97 Rhynie to Kildrummy road at Mossat yesterday.
The two-vehicle collision, which involved a motorbike and a car, happened at around 12.25pm.
Two ambulances attended the scene.
The road remained closed last night from the junction with the A944 Alford to Lumsden road at Mossat, with local diversions in place.
Officers have advised drivers to avoid the area and seek alternative routes.
A police spokeswoman said: “We received the call at 12.25pm. It is a crash involving a car and a motorbike.
“Ambulance are in attendance at the scene.”
She added that a person had suffered serious injuries, though last night neither the police nor ambulance service were able to provide further details.
A spokesman for the Scottish Ambulance Service said: “We received a call at 12.34pm today to attend an incident on the A97 in Aberdeenshire.
“We dispatched two ambulances to the scene.”
The road remained closed late last night, with police unable to indicate when it might be reopened to motorists.
The accident happened between Mossat Trout Fishery, and the Old Bridge Cottage which in 2016 was gutted by fire.
The area has been the scene of several serious accidents involving motorbikes in recent years.
A motorcyclist was airlifted to hospital after crashing on the A97 at Kildrummy in 2014, while a motorcyclist was killed when he collided with a car near Lumsden in 2012.