Ashya King, five, had been taken from Southampton General Hospital by his father Brett King, 51, and mother Naghemeh, 45, against medical advice.
Last night police confirmed he and his family had been found at a hostel on the Costa Del Sol, just hours after a European arrest warrant had been issued for his parents.
Hampshire Police said: “Ashya has been found. He is in Spain with his mum and dad. Police are speaking to his mum and dad and we are waiting to hear on Ashya’s condition.”
It is not clear whether any crime has been committed in the taking of Ashya, who has been receiving treatment for a brain tumour.
His father questioned the need for a European-wide hunt for his family when he said he had done nothing wrong.
In a video posted on YouTube last night, his father, a property developer, was seen holding his son, who appeared to be hooked up to a feeding machine.
He said: “As you can see, he is fine. Since we took him out of hospital he has been smiling a lot more.”
The family was reported to be not far from the Marbella villa they own. Ashya King’s family took him from Southampton General on Thursday afternoon and travelled on a ferry to France some two hours later. Hampshire Constabulary were told by the hospital that the youngster was missing at 8.35pm that day – more than six hours after he was taken by his parents.
Earlier, Assistant Chief Constable Chris Shead said: “I can confirm we have obtained a European arrest warrant. What that will do is, when we find Ashya and his family, it will allow us to talk to his parents about what happened.
“Clearly we need to find out what their motive is in taking Ashya.”
Shead said the European arrest warrant was based around “neglect” but added: “That does not necessarily mean they would be charged with that offence.
“It purely gives us the power to arrest and then we’ll be able to speak to them.”
Shead said the arrest warrant had been issued for Ashya’s parents and not his six siblings with whom they are travelling.
“We don’t want the family to be put off by the fact that there is an arrest warrant,” he said.
“We would much sooner they speak to us and get Ashya the care he desperately needs.”
Shead said the battery on Ashya’s feeding system “will have expired” and police had a “shrinking window” to find him, but King said in the YouTube video last night that he was being well cared for.