Djukanovic's European Montenegro coalition has won 39 out of the 81 seats in the future parliament, CEMI said in a statement released late on Sunday after the ballots from 94.4% of the polling stations were counted.
The leading opposition party, the Democratic Front, was polling second with 20 parliamentary seats, followed by the pro-Serb Socialist People's party with nine seats.
Sunday's vote was the third since Montenegro gained independence from Serbia in 2006.