Monday's ruling by tribunal President Theodor Meron reinforced earlier denials by the U.N. court's registrar and trial judges of a request by British lawyers Steven Kay and Gillian Higgins to back out of the landmark case.
The lawyers sought their own dismissal because Milosevic was undermining their attempts to present his defense, and many of his witnesses refused to testify.
Milosevic, who faces 66 counts of war crimes, refuses to recognize the legality of the tribunal and calls it anti-Serbian and a tool of his opponents in the Western governments.
Trial judges had assigned defense lawyers to Milosevic against his will because of his repeated trouble with high blood pressure and exhaustion, which has led to several months of delays.
Despite his weak health, Milosevic, 63, has been granted the right to conduct his own defense and this year began presenting his case. Last week, he again came down with the flu. His case opened three years ago this week.