The Personal identification number (Croatian: Osobni identifikacijski broj or OIB) is a permanent national identification number of every Croatian citizen and legal persons domiciled in the Republic of Croatia.
OIB is determined and assigned by the Tax Administration (Porezna uprava) of the Croatian Ministry of Finance.
OIB consists of 11 digits which contain no personal information, unlike the previous unique identification number scheme.
For the purposes of international data exchange, the letters HR are added preceding the eleven digits.
Starting with 1 January 2011, it became illegal to collect JMBG's where OIB would have sufficed, because under Croatian law, JMBG is considered to be a piece of personally identifiable information that is protected under the law on the protection of personal information, whereas OIB is not.