Tony Nicklinson, 59, fought a High Court battle for doctors to be allowed to end his life at a time of his choosing in the knowledge that they would not face a murder charge. The High Court refused his request last week and decided that it was up to Parliament to change the law.
He refused food after the decision and died at his home in Melksham, Wiltshire, today with his wife Jane, daughters Beth and Lauren, and his sister Ginny by his side.
Solicitor Saimo Chahal told reporters at a press conference: "I am extremely sad to tell you that I received a call at 10:45am from Jane Nicklinson to inform me that her husband Tony died peacefully at home at about 10am this morning.
"Jane told me that Tony went rapidly downhill over last weekend, having contracted pneumonia.
"He had made an advanced directive in 2004 refusing any life-sustaining treatment and also refused food from last week."
Mr Nicklinson was left paralysed from the neck down after a stroke during a business trip to Athens in 2005. He was unable to speak and could only communicate using a computer device that recognised his blinks or moves of the head.
He once described his life as a "living nightmare".
His right-to-die campaign was opposed by pro-life groups, including Care Not Killing, which said that the High Court had made the right decision in protecting the vulnerable.
A spokesperson for Care Not Killing said of the ruling: "Disabled people are all the safer for this welcome result."
The group said today that it would not comment on Mr Nicklinson's passing out of respect for his family.