Kostadinova was voted Sportsperson of the Year in Bulgaria four times (1985, 1987, 1995 and 1996).
Kostadinova is the reigning world record holder in the women's high jump at 2.09 m, which she jumped during the 1987 World Championships in Athletics in Rome. Her world record is one of the oldest in modern athletics. Altogether Kostadinova set seven world records - three outdoors and four indoors. She also holds the distinction of having jumped over 2.00 m 197 times.
In 1995 Kostadinova gave birth to her son, Nikolay, just several months before winning gold in the 1995 World Championships in Athletics. In 1999 she divorced her long-standing husband and coach, Nikolay Petrov. 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. In 2007 Kostadinova married her companion of some nine years, a businessman in the construction industry, Nikolai Popvasilev. 
Kostadinova won the gold medal in the 1996 Summer Olympics in Atlanta, setting an Olympic record of 2.05 m. She also won a silver medal at the 1988 Summer Olympics in Seoul. Kostadinova won the outdoor World Championships in 1987 and 1995. She won the World Indoor Championship five times between 1985 and 1997. Kostadinova also won gold in all European Championships in Athletics in which she competed. She was a European outdoor champion in Stuttgart in 1986 and a four-time European indoor champion in 1985, 1987, 1988, and 1994.
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). She jumped 1.66m and was informed that it was a world record for her age group; equivalent to the adult female world record in 1941: See Women's high jump world record progression