The fire broke out from an unknown cause, while strong firefighting forces are on the scene.
The mayor of Istanbul, Ekrem Imamoglou, arrived on the scene, while around 80 patients had to be transported away from the burning building.
So far there are no reports of dead or injured.
According to CNN Turk, citing firefighters, the fire was brought under control without any casualties.
The fire, according to the images broadcast by the television networks, started on the roof of the hospital and quickly spread to the exterior cladding of the building.
The head of the local municipality, Hasan Tahsin Usta, told TRT television that patients were taken out of the building.
Some patients were carried in arms
The images from the evacuation of the hospital are shocking, as some patients with mobility problems had to be transported in wheelchairs, or even on the backs of other citizens, in order to be rescued.
Η Σονάτα του Σεληνόφωτος, ο σκηνικός μονόλογος του μεγάλου ποιητή Γιάννη Ρίτσου, θα παρουσιαστεί για μία μοναδική βραδιά τη Δευτέρα 2 Φεβρουαρίου στο θέατρο Ολύμπια «Μαρία Κάλλας».
Στις 30 και 31 Ιανουαρίου, στο Ολύμπια θα πραγματοποιηθεί η συναυλία «Δύο Επέτειοι, Μία Σκηνή» - αφορμή τη συμπλήρωση 30 δημιουργικών χρόνων του συνθέτη Κώστα Λειβαδά και για τα 40 χρόνια της Ορχήστρας Νυκτών Εγχόρδων «Θανάσης Τσιπινάκης» του Δήμου Πατρέων.