Milosevic's Socialist Party of Serbia organised the arrival of supporters of the ex president Yugoslav president from all parts of Serbia, Belgrade electronic media reported.
The commemoration is broadcast live by Belgrade's BK Television.
Milorad Vucelic, a senior official from Milosevic's Socialist party, read out a statement of the funeral committee saying that the Milosevic family would not attend the funeral because of "some controversial statements made by the Serbian authorities regarding the Milosevic family safety and particularly because of threats and blackmails against Mirjana Markovic".
The mourners held a minute's silence and then broke into cries of "Slobo, Slobo!" and "This is Serbia!"
"Today we are bidding farewell to the best man among us," Vucelic told the crowd.
The commemoration continued with speeches by Socialist party officials.
Milosevic, who was denied the state funeral, is to be laid to rest in the afternoon in the garden of his family's provincial home in Pozarevac, east of Belgrade.