The 32-year-old world No. 1 pulled out of the Australian Open citing personal reasons before announcing that he had tested positive for Boldenova -- an anabolic steroid -- which he claimed was the result of eating Colombian meat.
"Mr. Farah's account of how the Boldenone entered his system was accepted and it was determined that he bears no fault or negligence for the violation within the meaning of Programme Article 10.4," a statement said.
"Where a finding of no fault or negligence is made, Programme Article 10.4 provides that any otherwise applicable period of ineligibility shall be eliminated entirely."
Canadian-born Farah, who along with long-time partner and fellow Colombian Juan Sebastian Cabal were the ATP's doubles team of the year in 2019, was provisionally suspended from January 21 but is now free to resume playing.
The decision is subject to appeal by the World Anti-Doping Agency (WADA) and NADO Colombia (COLDEPORTES) to the Court of Arbitration for Sport (CAS).