Since 1997, the Slovak car registration plate number (Slovak: EČV, evidenčné číslo vozidla) generally takes the form XX-NNNYY, where XX is a two letter code corresponding to a district (okres), NNN is three digit number and YY are two letters (assigned alphabetically).
Since May 1, 2004 (Slovakia joined the European Union) there are two forms of car registration plates valid in the country - with the Coat of Arms of Slovakia and also with the European flag.
Since June 1, 2006 there are three forms of car registration plates valid in Slovakia. The latest type contains the EU symbol as well as the national coat of arms (instead of a dash). As such, there are now three valid registration plates forms.

Older form
The older form (Slovak: ŠPZ, štátna poznávacia značka) XX-NNNN or XXY-NNNN - was issued until April 1, 1997. It stopped being valid as from January 1, 2005. Vehicles with this form are not allowed to ride on public roads.