Their cases were taken up by the Lausanne-based court after Russia's athletics federation was suspended by governing body IAAF, following revelations of a massive, government-supported doping programme.
WADA made 'mistakes' with meldonium ban: Andy Murray
The CAS ruling concerned racewalkers Vera Sokolova, Elmira Alembekova, Ivan Noskov, Mikhail Ryzhov and Denis Strelkov, who all tested positive for blood boosting endurance enhancer EPO in June 2015.
"All five athletes have been found to have committed an anti-doping rule violation," CAS said in a statement, adding that their suspensions would retroactively be counted from mid July 2016.
Will fight for those not going, says Rio bound Russian athlete
The ruling is the latest blow to Russia's beleaguered athletics programme, which was barred from the Rio Games and is at the centre of a unprecedented doping scandal that led the International Olympic Committee (IOC) to seek a complete overhaul of global drug testing.
The IOC at the weekend called for all testing and sanctioning powers to be taken away from sports federations.
It wants the World Anti-Doping Agency (WADA) to set up a new global testing body and CAS to make all decisions on punishments for those caught cheating.
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