Hungary's constitutional court annulled Tuesday part of a controversial law that ended official recognition and state funding for scores of religious communities, AFP reported.
The law had notably excluded Islamic, Buddhist and Hindu congregations, prompting heavy criticism from the international community.
"The Court believes that the regulations on obtaining status and recognition was unconstitutional and dependent on political decisions made in parliament," it said in a statement.
It also criticized the fact that parliament was not required to explain its decisions on whether a religious community obtained official status or not, and the lack of a right to appeal.
"The regulations must be transparent and objective," the court said, according to AFP.
The decision is retroactive and all the religions that were deprived of their status must have their recognition restored, it said.
Parliament approved a law in December 2011 that reduced the number of recognized faiths from over 300 to just 14.
Among the recognized faiths were so-called traditional religions like the Catholic, Reformed, Evangelical and Orthodox churches and Judaism.
However Islamic, Buddhist and Hindu congregations were excluded.
Tuesday's decision was the court's latest challenge to Prime Minister Viktor Orban's government, which has increasingly accentuated Hungary's Christian heritage.
In January it annulled a law on electoral procedures and voter pre-registration which was widely predicted to tilt general elections in 2014 in favor of Orban's right-wing Fidesz party.