[3] Born in Plovdiv, Kostadinova went to a specialist sports school, but was only introduced to high jump in a Year Six (12–13-year-olds) athletics meet in Sofia, on a day she is quoted as saying she would never forget (on TransWorldSport interview in 2012).

Kostadinova was reigning world record holder in the women's high jump until July 2024.

In 1995 Kostadinova gave birth to her son, Nikolay, just several months before winning gold in the 1995 World Championships in Athletics.

The same year she officially put an end to her athletic career, though she had actually not participated in any major sports competition since the World Indoors Championship in 1997.

She replaced Ivan Slavkov, who was expelled by the International Olympic Committee for violating its standards in ethics.