Cornelia Oschkenat, (née Riefstahl, born 29 October 1961) is a German former track and field athlete who represented East Germany. She competed at the 1988 Olympic Games in Seoul. At the 1987 World Championships in Rome, she won a bronze medal in the 100 meter hurdles with a time of 12.46s as well as silver medal as a member of the East German 4x100 meter relay team. She also won the 1987 World Indoor 60 m hurdles title, two World Cup 100m hurdles titles and three European Indoor 60 m hurdles titles. Her world indoor record for the 50 metres hurdles of 6.58 secs in 1988, still stands (as of 2014).
Oschkenat was born Cornelia Riefstahl in Neubrandenburg, Mecklenburg-Vorpommern, East Germany. She began her international career in 1982 and reached the World Championship final in 1983. She was unable to participate in the 1984 Olympic Games in Los Angeles because of her country's boycott of the games. In 1985, she won the World Cup title in Canberra. In 1986 she won a silver medal behind Yordanka Donkova at the European Championships in Stuttgart. She won perhaps her biggest individual title in 1987, at the World Indoor Championships in Indianapolis, when she won the 60 m hurdles, finishing ahead of her two chief career rivals, the Bulgarian pair of Donkova and Ginka Zagorcheva. Later that year at the World Championships in Rome, she won bronze in the 100 m hurdles behind Zagorcheva and East German teammate Gloria Siebert, but ahead of Donkova, who was fourth.
A medal favourite for the 1988 Seoul Olympics, she pulled a muscle midway through the final and limped over the line in 8th place. After finishing third at the 1989 World Indoor Championships, she went on to have one of her best ever outdoor seasons. Her victories included both the European and World cup events. She ended the outdoor season unbeaten. Having been ranked second in the Track and Field News world merit rankings for three consecutive years, 1985–87, she was the clear number one in 1989. In 1990, she finished fourth at the European Championships in Split in what would be her eighth consecutive (and final) year ranked in the world top ten (on time and merit). She represented a united Germany at the 1991 World Championships in Tokyo but was eliminated in the heats and retired at the end of that season.
Oschkenat represented the Dynamo Berlin sport club. During her career she was 1.76 meters tall and weighed 65 kilograms. She married fellow hurdler, Andreas Oschkenat in 1984.