Yugoslavian postal codes were introduced on January 1, 1971 and consisted of five digits. The first two digits roughly corresponded to the routing zones, mostly matching each of the Yugoslav republics: 1, 2 and 3 for Serbia, 4 and 5 for Croatia, 6 for Slovenia, 7 for Bosnia and Herzegovina, 8 for Montenegro and 9 for Macedonia. District seat cities usually had 000 as the last three digits, while smaller towns and villages had non-round last three digits.
Former Yugoslav postal codes are still used in the successor states of Serbia and Montenegro. North Macedonia and Slovenia removed the first digit and the remaining four digits continue to be in use. In Bosnia and Herzegovina, postal codes were adapted to new administrative structures. Croatia and Kosovo have new postal code systems.