Timothy Healy, 57, would inject drugs into some of his patients - several of whom were young boys - and abuse them when they fell unconscious.
Many victims were unaware they had been abused until police showed them the tapes.
In the Southwark Crown Court, Judge Geoffrey Rivlin described Healy's acts as "outrageous".
"You abused your position as a doctor.
"It was a hideous betrayal of your responsibility."
Healy committed most of the attacks between October 1978 and February 1988.
He admitted 31 charges of indecent assault, administering stupefying drugs to his victims, taking obscene photographs and possessing obscene material.
Lesser sentence
The assaults took place when Healy was working at surgeries at Southern Road, East Finchley and Abbots Gardens, Finchley.
The maximum sentence available was life imprisonment but a lesser sentence was passed because Healy pleaded guilty at the earliest opportunity.
He denied 12 similar offences and these have been left on the court file.
Detective Constable David Page, of the Scotland Yard Paedophile Unit, was pleased with the result.
"We have put an evil doctor behind bars," he said.
Healy, a bachelor, was arrested at Gatwick Airport in May last year by officers from the Paedophile Unit as he returned from a trip to Tunisia.
Police had been alerted by an anonymous tip-off.
Doctor suspended
Detectives believe he had been part of a paedophile ring and two other men have been convicted as the result of the seizure of about 10,000 items from the doctor.
Mr Page described Healy as "the most arrogant sex offender I've ever dealt with".
The General Medical Council has already suspended Healy and a decision to strike him off the medical Register is expected to be a formality.
Mr Page said police were yet to identify all the victims on tapes seized from Healy.