One of the plaintives (left) whose son was killed in the bombing
Six people have brought a case on behalf of the station's employees, saying the attack, which killed 16 people, was in breach of Europe's human rights charter.
They say the air strikes were illegal under the charter, which governs the right to life and freedom of expression. They are asking for compensation.
The hearing is only the first step to determine if the European Court of Human Rights (ECHR) has the jurisdiction to hear the case.
The lawyers for the 17 defendants - the European members of Nato - argued on Wednesday that the human rights court does not have the right to judge because the bombing took place in a country which is not a signatory to the European Convention of Human Rights.
Christopher Greenwood, a British government lawyer arguing for the defendants, also stressed that the two Nato members that played a central role in the Kosovo campaign - the United States and Canada - are not named in the suit.
And he pleaded that "Nato countries made the decision all together. They all agreed to these operations."
But plaintiff attorneys accused the 17 defendants of trying to hide under "the Nato umbrella," even though every Nato member state holds a veto over any major alliance action.
One lawyer, Hurst Hannum, argued that the court had already set the precedent that member states can be held accountable for acts committed outside their territory.
Propaganda war
On the night of 23 April 1999, Nato aircraft attacked the government-run studios of Radio Television Serbia (RTS) in Belgrade, in which those killed, most of them production workers, had been ordered to report for work.
The attack was part of Nato's air campaign to force the Yugoslav Government of former President Slobodan Milosevic to withdraw its forces from Kosovo.
At the time, Nato defended the air strike by saying the TV station was a legitimate target because of its role in what Nato called Belgrade's campaign of propaganda.
The court's 20 judges have now retired to decide on the case's admissability.