The princess said the experience left her feeling angry and upset
The plight of abandoned children in a Turkish orphanage made Princess Eugenie cry, pictures show.
She accompanied her mother the Duchess of York and an undercover news team to investigate conditions in an Istanbul centre for 60 disabled children.
Afterwards the princess said the experience had made her "so angry", and her "eyes had been opened".
The Royal pair also visited Romanian institutions as part of the special report for ITV1's Tonight programme.
The princess told Tonight: "In the hustle and bustle of a cosmopolitan city, in a popular tourist destination it's hard to comprehend places like that exist. My eyes have been opened."
The duchess donned a wig and headscarf disguise
She wore a disguise of a black wig and headscarf to visit the Saray institution near the Turkish city of Ankara, where more than 700 disabled children are housed.
Inside she and the reporting team found children tied to their beds or left in cots all day - not even being taken out to be fed.
One child, who was not allowed outside, was discovered crawling along the corridor to feel the sun on his face.
Her sister Princess Beatrice also went with her mother to institutions in Romania with the programme.
The duchess, who works with a number of children's charities, wanted to see for herself whether conditions were improving for orphans and disabled children in Romania following a similar investigation by the team three years ago.
The duchess said: "Everybody always rushes to what the front page says, or what's sexy, or the glamorous Hollywood party where you're raising money for paediatric aids, which is fantastic and a great job.
"But there is still a child in Romania saying 'help me'."
The programme will be broadcast on ITV1 on 6 November.