Jedlicka presented "citizenship certificates" to people who had gathered on Friday evening in an attempt to reach the Danube island he had declared "a state", but were turned back by Croatian border police.
Jedlicka and the new citizens of Liberland then gathered in a restaurant outside Backi Monostor where the first 100 citizenship certificates were presented and a party was held.
Tanjug said that about 300,000 people had applied for citizenship and that Jedlicka had announced that "general elections" would be held soon.
Jedlicka, a Czech, has declared a no man's land Danube island a state and called it Liberland. He claims that the state was established in full compliance with international law because it was founded on a piece of no man's land which neither Serbia nor Croatia claim as their own.
He said his aim was to create a society where decent people could prosper without the state making their lives difficult with unnecessary bans and taxes.
Liberland has a flag, a coat of arms, a constitution and laws, and is willing to grant its citizenship to anyone provided they are not Communists, neo-Nazis, extremists or people convicted of serious crimes, according to media reports in the northern Serbian province of Vojvodina.