The animal had been standing close to the fence at the zoo when the bizarre incident occurred.
In footage filmed by an onlooker, the man can be seen clambering over the fence.
When he reaches the top, he stretches out to stroke the animal’s neck.
The huge animal appears relaxed so the man then decides to jump over the fence and onto its back.
He manages to hold onto the giraffe for several seconds, before it darts off and throws him off its back.
In the last seconds of the footage, the giraffe is seen coming back and the scared man quickly scrambles back over the fence where he then escaped before he could be arrested.
The incident took place at Shymkent Zoo in Kazakhstan and police have now confirmed they are trying to identify the man, who faces arrest over the stunt.
Local media reports claim he had been drunk at the time.
The Shymkent Zoo is one of the most popular tourist attractions in the country spread over 130 acres and has over 1,500 animals, including a herd of giraffes.
It also includes 20 animals that are on the critically endangered “red list”.
The video comes just days after a huge gorilla was filmed trying to attack tourists at London Zoo – after appearing to get angered by a woman’s T-shirt.