Around 1,000 people have marched through Bucharest amid proposals to amend the constitution and ban gay marriage. Orthodox Church groups claim to have 3 million signatures in support of the plan.
Saturday's gay pride march took place amid a carnival atmosphere in the Romanian capital, despite anger at moves to curtail gay marriage.
Recently, lawmakers supported a plan that could see part of the country's constitution rewritten to explicitly state that marriage is a union between a man and woman. The text, which currently allows for marriage between "spouses," will now be put to a public referendum.
Denouncing the proposals, gay rights' activist Florin Buhuceanu told the Agence France-Presse news agency that authorities "want to use democratic means to undermine democracy and deprive certain social groups of the protection due to them."
Another demonstrator, Radu, told AFP that "it's important to support all citizens, regardless of their sexual orientation."
Vlad Viski, chairman of the gay rights' group MosaiQ, insisted that "gay couples are a reality," telling The Associated Press that Romania must legalize civil partnerships.
Several groups close to the powerful Orthodox Church have launched the "citizens' initiative" that will effectively see gay marriage banned if the referendum is approved.
The groups claim to have collected 3 million signatures from among the Romanian population of nearly 20 million.
In response, Saturday's protesters, waving rainbow flags and carrying umbrellas amid a heavy downpour, called for a "separation between the church and the state."
Criticism from diplomats, MEPs
Thirty-three members of the European Parliament (MEPs) have also called on parliament not to "support the referendum," which they said was likely to "permit the continuation of discrimination already present in Romanian society."
US Ambassador Hans G. Klemm also took part in Saturday's march, which received support from some 30 international diplomats despite being frowned upon by many Romanians.
At one point, a minute's silence was held in solidarity with gay people being detained and tortured in Chechnya because of their sexuality.
Patrick Braila, a Romanian movie director and gay rights' activist, called for marchers to remember gays in Chechnya and Romanians who had moved abroad due to discrimination.
Romania decriminalized homosexuality in 2001.
Earlier in the day, a small counter-march was held by far-right parties, who said they were opposed to adoptions by same-sex couples.
mm/cmk (AFP, AP)