Baby Qiuqiu could fit into the palm of his mother's hand when he was born three months prematurely and he was no longer than a pencil.
He was the smallest baby that doctors at the Central South Hospital in Wuhan City, China, had ever dealt with.
After battling to save him for 16 weeks, doctors have finally given the tiny boy the all clear and he may soon be allowed to go home.
Qiuqiu's mother was just 28 weeks pregnant when she gave birth to him on January 9, this year.
"He was as big as the palm of a human hand and as a long as a pen," said one of the medical team that saved him.
Four months later, Qiuqiu is doing well. He has now quadrupled his weight and, apart from a problem with one lung, is making a good recovery.
This week doctors will take him off the ventilator and if he can breathe on his own, he should be able to leave hospital in a month's time.
Qiuqiu's status as the smallest baby ever born in the hospital has led to him being regarded as a lucky talisman by the staff, who have put pictures of him up in the entrance hall.
Qiuqiu is not the smallest baby ever to survive - that title belongs to Rumaisa Rahman, who was born in Illinois, US, on September 19, 2004, weighing just 9.17oz.