"Foreign Minister of Belarus Vladimir Makei has died," Anatoly Glaz said.
The cause of death was not specified. He had a wife and three children.
Russian Foreign Minister Sergey Lavrov was expected to hold a meeting with Makei on Monday.
The ministry's official website has not yet announced Makei's death. The site still carries its latest update of 25 November when it was reported that the head of the Foreign Ministry met with a representative from the Vatican.
Vladimir Makei had headed the Foreign Ministry of Belarus since August 2012. Before that, he had been in charge of the presidential administration for several years.