Tony Nicklinson, who failed in his high court bid to be allowed to end his life with the help of a doctor, has died just six days later, his lawyers said. He had been refusing food since the verdict, but contracted pneumonia and "went downhill quickly", they said.
Wiltshire police said they were not involved and it is believed the death was from natural causes.
In a brief statement, Bindmans LLP said Nicklinson, from Melksham, Trowbridge, died on Wednesday morning at home.
"This is to notify you of the sad death of Tony Nicklinson at approximately 10am this morning," the law firm said.
It also asked for the family's privacy to be respected.
Nicklinson's despair following last week's ruling was evident to all, as he broke into sobs that shook his paralysed body. He and his wife said they would appeal. "I believe the legal team are prepared to go all the way, but it means yet another period of physical discomfort and mental anguish for me," he said via a computer which he controlled through his eye movements.
In a statement at the time issued through his lawyers he said: "I am saddened that the law wants to condemn me to a life of increasing indignity and misery."
Although the judge acknowledged that his case and that of another paralysed man, known as Martin, were deeply moving, he said it was for parliament and not the courts to decide if the law should be changed.
Nicklinson, 58, was paralysed from the neck down after a stroke seven years ago. He wanted assurances from the court that anybody who helped him end his life would be free from prosecution.
A message posted from Nicklinson's Twitter account by his family on Wednesday said: "You may already know, my Dad died peacefully this morning of natural causes. He was 58. Before he died, he asked us to tweet: 'Goodbye world, the time has come, I had some fun.' Thank you for your support over the years. We would appreciate some privacy at this difficult time. Love, Jane, Lauren and Beth."
His wife, Jane, tweeted: "I have lost the love of my life but he suffers no more."
His daughter Beth added: "RIP @TonyNicklinson. Couldn't have asked for a better dad, so strong. You are now at peace, we will be fine. I love you xxx."