The 61-year-old Lukashenko received 83.49% of votes in Sunday elections, sufficient to avoid a runoff and enough to enable him to enter his third decade of leading his country.
Meanwhile Hundreds of protesters march in central Minsk after polls show President Alexander Lukashenko winning a fifth term by a landslide.
Lukashenko's re-election five years ago led to mass protests and the imprisonment of leading opposition figures, but support for his 20-year-old Presidency has risen since he cast himself as a guarantor of stability in the face of economic crisis and a pro-Russian separatist conflict in neighbouring Ukraine.
Nevertheless, his criticism of Russia's annexation of Ukraine's Crimea peninsula last year, his hosting of Ukraine peace talks and his pardoning of the six opposition leaders in August suggest he is seeking to improve his image in the West, observers say.
The central election commission said Lukashenko won 83.5 of the vote, slightly more than the 80 percent support registered in the 2010 elections, the head of the central election commission said in a briefing late on Sunday.
The West has long ostracized Lukashenko's Belarus, described in 2005 by U.S. Secretary of State Condoleezza Rice as "Europe's last dictatorship", over its alleged human rights record and clampdown on political dissent. It has imposed economic sanctions on some Belarussian officials and companies.