Professor Hawking, who had a tracheostomy inserted into his windpipe three decades ago after developing a condition called amyotrophic lateral sclerosis, said he was considered to be "so far gone" that doctors in Switzerland where the renowned academic fell ill considered disconnecting the ventilator.
Doctors later agreed for the A Brief History Of Time author to be flown back to England for further treatment, where he was able to lead close to a "full and active life".
The 72-year-old, speaking from his wheelchair through a computer programme to an audience at the Royal College of Surgeons, said: "I was rushed to hospital [in Switzerland] and put on a ventilator. The doctor said they thought I was so far gone they offered to turn off the ventilator.
"But I was flown back to Cambridge. The doctors there tried hard to get me back to how I was before."
The septuagenarian University of Cambridge lecturer was speaking at the launch of the European Global Tracheostomy Collaborative (GTC) in central London, where he was given a standing ovation by more than 200 delegates.