Old till 2005:

format - aa(a)0000
usual:
symbol - red, background - white

police:
symbol - white, background - red

Region - first letter:
А - Brest region
В - Vitebsk region
С,Х - Grodno region
Е - Gomel region
О - Minsk region
Т - Mogilev region
К,М - Minsk

New (since 2005):

format - 0000 aa-0

usual:
symbol - black, background - white

Region - last figure:

1 - Brest region
2 - Vitebsk region
3 - Gomel region
4 - Grodno region
5 - Minsk region
6 - Mogilev region
7 - Minsk

Belarus
Embassies and Consulates
Road distance
Photo from Belarus