The Israeli military body responsible for Palestinian civilian affairs, known by its acronym COGAT, said the transport was carried out in co-ordination with officials from the United States, Egypt and the international community.
The children and their companions left the Gaza Strip via the Kerem Shalom crossing, and the patients were to travel to Egypt and further abroad for medical treatment.
Travel out of the Gaza Strip has always been difficult, subject to intensive security checks by both Israeli and Egyptian authorities.
When the war began on October 7, it became far harder.
Since Israeli forces took control of the main Rafah border crossing into Egypt in the latest stage of their military campaign, travel has been almost impossible.
For parents with sick or injured children, their maladies worsened by nearly nine months of intense Israeli bombardment of Gaza that has pushed nearly all people from their homes and left the health system in tatters, the situation is catastrophic.
Buses have taken Gazan children with chronic diseases through the Kerem Shalom crossing. (AP PHOTO)
Little Fayez Abu Kwaik clung to his mother before he left for cancer treatment overseas without her, his arms around her neck and his face pressed into her as the tears ran down her cheeks.
Fayez, aged five, was in a group of children who have been cleared to leave the enclave for medical reasons.
His parents said Israel had not accepted their travel request so Fayez would go with his grandmother, whose application was approved.
"Lumps in his body have spread and we don't know what the reason is," his mother Kamela Abu Kwaik said.
"I am heartbroken. He has been unwell when he was with me, and he is unable to get treatment. How I am going to leave him when he is only five years old," she added.
The family do not know exactly where Fayez will be treated but they believe his best chance is joining the convoy of two buses and four ambulances to Egypt, via Israel, along with about 20 other children and accompanying adults.
In one ambulance a boy lay on a stretcher, his legs missing from above the knee.
A father stood holding his two little daughters, one of them bandaged across the head after suffering burns during Israeli bombardment, he said.
The conflict began when Hamas fighters raided Israeli communities on October 7, killing about 1200 people and abducting about 250 others according to Israeli tallies.
Israel's military response has involved an all-out ground and air campaign in Gaza, levelling swathes of the tiny enclave and killing at least 37,700 people and injuring 86,400 others according to Palestinian health authorities.
"Look at him. He is bursting from all the crying. What have they done to deserve this? He is five years old," Fayez's mother said.
"He says to me 'I love you - don't leave me'. What should I do? It's not in my control. Do you think I want to leave him?" she said, her voice breaking as he was carried to the bus.
Mohammed Zaqout, director of Gaza hospitals who had helped arrange the convoy, said there were more than 25,000 cases of illness and injury in the enclave that required treatment which could no longer be provided there.
Those cases included 250 children who required urgent treatment for life threatening problems, he said.
As the bus pulled away, a small child could be seen through a window, crying inconsolably.
with AP
9°C