Under the agreement, the two countries will extradite to one another their citizens or people without citizenship who are indicted and convicted for organised crime and corruption and who have permanent residence in the country which has received a request for extradition.
Speaking to reporters, Simonovic said the agreement was very important for relations between the two countries as well as for relations in the entire region and for Croatia's and Serbia's integration with the European Union.
"The agreement is proof of our strong determination to fight together against organised crime and other types of crime in the region. The agreement is a very important step in building trust between the two countries," said Simonovic.
He added that the agreement would very soon yield very concrete results and that it also must have a preventive role.
Serbia's Justice Minister Snezana Malovic said the agreement was of historic importance and was a result of the countries' common commitment to promoting cooperation in the field of judiciary.
The agreement will contribute to Serbia's integration with the EU and its fight against organised crime, as well as to the enhancement of relations with Croatia, Malovic said.
The two ministers said that the agreement would enter into force immediately and that its provisional enforcement would last until it was ratified by the two countries' parliaments.
Speaking about a possibility for extraditing Sretko Kalinic, known as a member of the so-called Zeun underworld gang who was in Serbia sentenced in absentia to prison for the assassination of Prime Minister Zoran Djindjic, Simonovic said Kalinic was now in detention in Zagreb over falsified passports.
In early June, Kalinic was admitted to a Zagreb hospital after he was seriously wounded in a shootout outside Zagreb.
Stressing that he could not prejudge a ruling of the relevant court on Kalinic's extradition, Simonovic said Serbia had forwarded a well-argued and comprehensive request for his handover. The request has been forwarded to the Zagreb County Court.
Simonovic also said that the brief extradition procedure when persons facing extradition do not appeal would take one month, and the procedure would last four months if all legal means are used by people facing extradition to appeal against it.