The victim ended up in West Beck at the bottom of Mallyan Spout waterfall after he slipped while using the New Wath Scare footpath at around 1.30pm on Tuesday.
He had fallen in the boulder field at the base of the Scar and landed around a metre from the edge of the bank having sustained a head injury.
Scarborough and Ryedale mountain rescue volunteers helped the ambulance and fire service to load him onto a bell stretcher, evacuate him from the gorge and carry him a distance upsteam to a location where the Yorkshire Air Ambulance could land.
He was then flown to James Cook University Hospital in Middlesbrough for further treatment.
The multi-agency rescue operation took three hours.
Walkers are warned that the footpath through the Scar can be dangerous during and following rainfall.