Landis, who was stripped of the 2006 Tour de France title for doping, gave the Wall Street Journal additional details about his use of banned doping products in a story published Saturday and again accused Armstrong and his teammates of receiving blood transfusions during the 2004 Tour.
In a statement sent to The Associated Press through his manager, seven-time Tour de France winner Armstrong described Landis' claims as "a carton of sour milk: once you take the first sip, you don't have to drink the rest to know it has all gone bad."
Landis told the newspaper that some of the bikes provided to Armstrong's team were sold in order to help the U.S. Postal team fund his doping program.
"Today's Wall Street Journal article is full of false accusations and more of the same old news from Floyd Landis, a person with zero credibility and an established pattern of recanting tomorrow what he swears to today," Armstrong said.
Landis also claimed in May that Armstrong tested positive for the banned endurance booster EPO at the Tour de Suisse in 2002 and paid off former International Cycling Union boss Hein Verbruggen to keep it quiet. Armstrong won the 2001 Swiss race, but did not compete there in 2002.
Armstrong, who is competing in his last Tour de France, has consistently denied any wrongdoing. The Tour starts later Saturday in the Dutch port city of Rotterdam.
"For years, sensational stories based on the allegations of ax-grinders -- have surfaced on the eve of the Tour for publicity reasons, and this article is simply no different," Armstrong said. "Lastly, I have too much work to do during this, my final Tour, and then after my retirement in my continued fight against cancer, to add any attention to this predictable pre-Tour sensationalism."