An internal report by the tribunal into Milosevic's death in his cell in March said on Wednesday: "Nothing has been found to support allegations reported in some sections of the media that Mr Milosevic had been murdered, in particular by poisoning.
"It cannot be concluded that there was a failure to provide proper care by those treating Mr Milosevic."
Milosevic died in detention on March 11, months before the expected conclusion of his war crimes trial.
An investigation by Dutch prosecutors concluded in April that Milosevic died of a heart attack with no sign of poisoning.
Toxicological studies showed no traces of poisoning or substances that could have caused a heart attack.
But speculation continued over whether Milosevic took drugs to exacerbate his high blood pressure to strengthen his case for release for medical treatment in Russia, where his wife and son live.
Milosevic's family accused the court of murdering him by refusing to let him travel to Russia for treatment.
"Nothing has been found to support allegations reported in some sections of the media that Mr Milosevic had been murdered, in particular by poisoning"
Milosevic's lawyer said his client wrote to Russia a day before he died saying he feared that he was being poisoned.
"On a number of occasions, Mr Milosevic refused to accept the advice of his treating doctors. He refused to take some prescribed medications and varied prescribed dosages of others. He also self-medicated," the tribunal report said.
As the tribunal had granted Milosevic the right to defend himself, he was given a private office with a telephone and computer, where he could meet witnesses and his lawyers.
One Russian witness admitted smuggling in non-prescribed medicines.
The tribunal report said that the arrangements to enable Milosevic to conduct his own defence compromised security, but said expert opinion was divided over whether surgery could have prevented Milosevic's death.