The former world number one from Russia has succeeded in having her suspension reduced.
An arbitration panel "found that Ms Sharapova committed an anti-doping rule violation and that while it was with 'no significant fault', she bore some degree of fault, for which a sanction of fifteen months is appropriate," Switzerland-based CAS said in a statement. The ban took effect from Jan. 26, 2016.
Five-times grand slam winner Sharapova was banned by the International Tennis Federation in June following a positive test for the banned drug meldonium during January's Australian Open.
Five-times grand slam winner Sharapova was banned by the International Tennis Federation (ITF) in June following a positive test for the banned drug meldonium during January's Australian Open.
The former world number one from Russia sought to have her suspension wiped out or reduced.
She had called the ITF's ruling "unfairly harsh" as an independent tribunal had found that she had not intentionally violated anti-doping rules.
Sharapova, 29, admitted taking meldonium during the season's opening grand slam in Melbourne but said she had been unaware that it had been banned by the World Anti-Doping Agency (WADA).
Meldonium was added to WADA's list of banned substances at the start of the year after mounting evidence that it boosted blood flow and enhanced athletic performance.