In the eastern town of Pozarevac an elderly couple froze to death in their home, and a man died in the mountainous Sjenica region in the southwest, police said.
Temperatures fell as low as minus 15 degrees Celsius.
Sections of the highway linking capital Belgrade and the southern city of Nis were closed, and remote villages in central Serbia remained cut off for the third day.
Roads linking Belgrade with the Romanian border were also closed to traffic, Serbia's Drivers' Association said.
In neighbouring Montenegro, dozens of local roads remained closed while repair crews continued work after nearly 48 hours to restore power supplies to the Adriatic port of Bar and the town of Ulcinj near the Albanian border.
Montenegro's largest airport in the capital, Podgorica, was reopened for traffic for the first time in two days.
Croatian media said some roads in mountainous areas were closed, and severe gales halted ferry traffic between the mainland and some Adriatic islands.
In northern Albania, an avalanche blocked 13 cars on Thursday, while the government used helicopters to evacuate the sick from remote areas.
Authorities in Kosovo blamed snow and low temperatures for about 100 traffic accidents in the past 24 hours, in which 16 resulted in injuries.
Last Mod: 20 Şubat 2009, 15:41