A motorbike rider and pillion passenger were airlifted to hospital following a collision on the A591.
Police, ambulance and two air ambulances attended the incident at Wythburn near the Thirlmere reservoir at 1.20pm on Friday.
The collision involved a black Vauxhall Corsa and a Kawasaki motorbike.
The rider and pillion passenger on the motorbike were taken by air ambulance to Royal Preston Hospital with serious injuries.
The road remained closed for several hours while a forensic collision examination was commenced.
Police are appealing for witnesses who may have seen the collision or who may have driven between Grasmere and Thirlmere who have dashcam footage that may have captured the vehicles before the collision.
Contact Cumbria police by emailing [email protected] or 101 quoting log number 98 on the 25th March and ask for PC2671 Colin Dunne or PS1489 Lee Hill.