The resolution criticised official harassment since the election
A key UN committee has voted to approve a non-binding resolution condemning Iran for its crackdown on protesters following June's disputed elections.
The resolution also repeated annual criticism of Iran's human rights record, including the use of torture and an increasing execution rate.
It urged Tehran to end persecution of political opponents and release those imprisoned for their political views.
Iran's UN ambassador dismissed the resolution as politically motivated.
Mohammad Khazaee said such measures had "created an atmosphere of confrontation and polarisation" at the UN.
Friday's text was approved by 74 votes to 48 with 59 abstentions, which the US said was "the largest vote margin on such a resolution on Iran in the UN ever".
Deputy state department spokesman Robert Wood said it demonstrated the international community was "deeply concerned" about the human rights situation in Iran.
The resolution expresses "deep concern at serious ongoing and recurring human rights violations" in Iran.
But it said there was "particular concern" at the Iranian government's response to the 12 June elections and the "concurrent rise in human rights violations".
It comes as the major powers said they were disappointed with Iran's response to an offer of a deal over its nuclear programme.
President Mahmoud Ahmandinejad was declared the winner of June's election, resulting in large scale protests by supporters of opposition candidates who said the poll had been rigged.
The UN committee criticised the subsequent "harassment, intimidation and persecution, including by arbitrary arrest, detention or disappearance" of opponents of the government.
It also condemned alleged abuses of those in prison and "numerous deaths and injuries" in the crackdown.
The BBC's Barbara Plett in New York says some of those countries which did not vote for the resolution did have concerns about the state of political rights in Iran, but objected to the practice of singling out specific countries for condemnation.
Saudi Arabia broke ranks with Muslim nations and voted in favour of the resolution, possibly because it accuses Iran of backing Shia rebels in neighbouring Yemen, says our correspondent.
On Friday, following meetings in Brussels, the six world powers negotiating with Iran said they were disappointed by Tehran's failure to respond positively to a recent deal on its nuclear programme.
Iran has rejected the offer, which would allow it to continue to develop a nuclear reactor by exporting uranium to other countries to be enriched.