The IAAF first imposed the ban on the All-Russia Athletics Federation (ARAF) last November, then upheld it in June.
"CAS rejects the claims/appeal of the Russian Olympic Committee and 68 Russian athletes," the court said on its website.
The athletes may submit appeal during 30 days, CAS secretary general stated.
Lausanne-based CAS heard ROC’s claim against the IAAF ban on July 19 in Geneva.
Russian pole vaulter Yelena Isinbayeva represented Russian athletes in the case, alongside British lawyer Mike Morgan, ARAF President Dmitry Shliakhtin and Secretary General Mikhail Butov, as well as ROC head of legal department Alexander Brilliantov.
The International Olympic Committee said it would explore legal options ahead of deciding whether to ban the Russian national team from the Summer Olympics in Rio next month.
An IOC spokeswoman suggested the decision would be forthcoming within a week, while several reports indicated the decision could be made this weekend.
More about:
