The Tinkoff-Saxo rider was provisionally suspended by the International Cycling Union (UCI) earlier this month after cycling's governing body announced the 28-year-old was under investigation for alleged abnormalities in his biological passport.
Czech Kreuziger challenged the decision and took his case to CAS in an attempt to be cleared to race in the Vuelta a Espana, which starts on Saturday, and the UCI World Road Championships in Spain next month.
CAS on Wednesday revealed that Kreuziger had failed to get his suspension lifted.
A statement released by CAS said: "The Court of Arbitration for Sport (CAS) has dismissed the appeal of the Czech cyclist Roman Kreuziger against the decision taken by the Anti-Doping Commission of the International Cycling Union (UCI) to provisionally suspend him from competition pending an investigation into a possible anti-doping offence.
"The rider sought to overturn such suspension in order to be able to compete in the 2014 Tour of Spain and possibly in the UCI World Road Championships.
"Roman Kreuziger filed an appeal at the CAS on 5 August 2014. In accordance with the rider's request and the UCI's agreement, the arbitration procedure was conducted on an expedited basis.
"The panel of CAS arbitrators (Prof. Michael Geistlinger, Austria (President), Mr Lars Nilsson, Sweden, and Mr Bernhard Welten, Switzerland) heard the parties during a hearing held at the CAS headquarters from 9:30 to 12:30 today.
"Accordingly, Roman Kreuziger remains provisionally suspended pending a decision on his alleged anti-doping rule violation.
"The full award with the grounds will be issued in a few weeks."