Peter Tobin, 47, was told by Mr Justice Waterhouse that the girls had been seriously affected by his conduct and 'it may well be their prospects in life have been gravely and permanently impaired'.
Winchester Crown Court had heard that one of the girls, who was a virgin, was threatened with a knife and forced to swallow wine and tablets at Tobin's flat in Leigh Park, Havant, Hampshire, one night last August. While unconscious, she was raped and buggered.
Her friend, who had collapsed after being given a drink, awoke to find herself lying on the floor, with her jeans on the other side of the room, her knickers halfway down, and the other girl next to her. Tobin had left.
The girl raised the alarm and her friend was admitted to hospital. When police went to Tobin's flat they found a gas fire in the lounge was on but unlit. Tobin fled to Brighton, where he joined a religious group and, using a false name, immersed himself in its community at Stockton, Warwickshire.
After the hearing, Detective Inspector Andy Stewart said he was pleased with the sentence and glad Tobin's pleas of guilty had spared the girls from the further ordeal of having to give evidence.
'The families have lived with this extreme tragedy for the last nine months and only now will they feel able to rebuild their lives,' he said.
Tobin had admitted charges of rape and buggery of one girl, for which he was sentenced to 14 years concurrent on each, and indecently assault of the other, for which he was jailed for five years, also to run concurrently. His earlier pleas of not guilty to charges of attempted murder and false imprisonment were accepted by the Crown.
Anthony Davies, for the prosecution, said that on 4 August last year the girls had gone to the flats where Tobin lived to visit a woman. But she was not in and they went to Tobin's flat where he lived with his six-year-old son.
He plied the girls with cider and a vodka-based drink. He gave each girl two small tablets he referred to as 'blues', saying he had taken three that day. They pretended to take them but in fact put them in their pockets.
When one of the girls got up from the sofa she felt dizzy and fell. The other girl was sick in the bathroom and then attempted to wake her friend.
Tobin threatened her with a bread knife which he held to her throat and said that if she kept on crying he would kill her. He forced her to take some pills with wine, and she lost consciousness and was then raped and buggered.
The other girl woke at about 6.25am the next day and found a bloodied bandage around her wrists, a tie around her ankle and her friend next to her. After trying to wake her she went home and raised the alarm.
Tobin's membership of the religious community allowed him to remain undetected in Warwickshire. But he later returned to Brighton, where he was arrested last September.
Tobin had not lured the girls to his flat. One of them was a regular visitor and nothing improper had occurred before. The offences were wholly out of character.