The Thiruvananthapuram MP has already been summoned as an accused on July 7 in the case.
Special Judge Arvind Kumar granted Tharoor the relief on personal bond of Rs one lakh while directing him to neither tamper with evidence nor leave the country without the court's prior permission.
Pushkar was found dead in a suite of a luxury hotel in the city on the night of January 17, 2014.
In his plea for anticipatory bail, Tharoor had submitted that the charge sheet in the case was filed and the Special Investigation Team (SIT) had categorically stated that the probe was concluded and that his custodial interrogation was not required.
The court had summoned him as an accused in the case on June 5, asking him to appear before it on July 7 observing that there were sufficient grounds to proceed against him.
Tharoor has been charged under Sections 498A (husband or his relative subjecting a woman to cruelty) and 306 (abetment of suicide) of the Indian Penal Code, but has not been arrested in the case.
Evidence of drug overdose in Sunanda's body
Sunanda's death: Shashi Tharoor is in big trouble
"I have no desire to live," Sunanda wrote to Tharoor: Police
Tharoor and Pushkar: A Twitter tragedy
Rejoinder: Time I put the record straight, says Shashi Tharoor