When Oprah asked Armstrong whether he used EPO and blood transfusion during his racing days, the 41-year-old American answered with a definite "Yes", reports Xinhua.
But he denied the US Anti-Doping Agency's accusation that he helped orchestrate a "most sophisticated, professionalised and successful doping program the sport has ever seen" while he rode for the US Postal Service team in the Tour de France.
"It was definitely professional, definitely smart but it was conservative," said Armstrong.
Armstrong was stripped of his seven Tour de France titles and banned for life as the USADA released a scathing report condemning him to be the centre of a "sophisticated" doping program while riding for the US Postal Service Team and Discovery Channel team between 1998-2005.
Hours before the airing of his interview with Oprah, the International Olympic Committee (IOC) decided to strip him of the bronze medal he won at the 2000 Olympic Games.