He Pingping, a smoker who stood just 2ft 5in tall, had been in hospital for several days after suffering chest pains.
He fell ill with suspected heart complications in Rome, where he was due to appear on a TV show.
Last night Guinness World Records chiefs paid tribute to Pingping, who suffered from primordial dwarfism.
Meeting ... He Pingping with 8ft 1in Sultan in January
Editor-in-chief Craig Glenday said: "He brightened up the lives of everyone he met and was an inspiration to anyone considered different or unusual.
"We are very saddened by the loss of such a wonderful, engaging, fascinating character."
In January, Pingping met the world's tallest man, 8ft 1in Sultan Kosen, 26, at a Guinness World Records event in Istanbul, Turkey.
He got the title of World's Shortest Man in 2008 and jetted from his home in Inner Mongolia to meet The Sun in London. At the time he said: "I just want a normal life, get married and have children." Sadly, he never got his dream.