Four-digit postal codes were first introduced in Romania in 1974. Beginning with 1 May 2003, postal codes have six digits, and represent addresses to the street level in major cities (those with population over 50,000). The digits represent (from left to right) the postal area; the county; the city/commune; the last three, depending on the size of the city/commune, represent the commune/city, the street, or the house/building.

The first digit represents the postal region, and the second the county in the postal region. Together, the first two digits identify a county.

The rest of the digits follow this convention:

List of codes