Sharapova admitted in March that she had tested positive for the substance but claimed that she had been taking it for heart problems since 2006.
In a statement, the ITF said the 29-year-old five-time Grand Slam champion's ban would be backdated to 26 January this year.
Meldonium was recognised as an illegal substance in January this year and the Russian said that she failed to read the email stating that the substance will be added to the list of banned substance in 2016.
According to the World Anti-Doping Agency, it was added to the list because of evidence of its use by athletes to enhance their performance.
Russia had planned to include the five-time Grand Slam champion in their Rio Olympic team but the ban now rules her out of the August games, however, she has confirmed on her Facebook page that she will be appealing the verdict.
