By 71 votes to 54, with 55 abstentions, the assembly on Monday said Tehran restricted free speech, used torture, and persecuted dissenters.
The resolution is not legally binding but is an expression of world opinion.
Meanwhile, Amnesty International says it fears an Iranian woman convicted of adultery may be buried up to her chest and stoned to death on Tuesday.
The human rights group has urged the Iranian authorities to grant a last-minute reprieve to the woman, Hajieh Esmailvand.
‘Serious concern’
The UN resolution condemning Iran was sponsored by Canada – whose relations with Iran have suffered since Canadian photojournalist Zahra Kazemi died in Iranian custody in June 2003.
The resolution expressed “serious concern” about the “continuing violations of human rights” in Iran – including restrictions on freedom of expression.
It said the persecution of those peacefully expressing political views had increased, citing “crackdowns by the judiciary and security forces against journalists, parliamentarians, students, clerics and academics; the unjustified closure of newspapers and blocking of Internet sites”.
The resolution also expressed concern at:
. the execution of children
. torture, as well as degrading punishments such as amputation, flogging and stoning
. discrimination against women and girls
. the persecution of political opponents, following last February’s mass disqualification of opposition candidates in the run-up to parliamentary elections
. discrimination against minorities, including Christians, Jews, Sunni Muslims, and in particular followers of the Baha’i faith, including arbitrary arrest and detention.
Meanwhile, Amnesty International says time may be running out for Ms Esmailvand, the Iranian woman feared to be facing death by stoning on Tuesday.
She is thought to be have been imprisoned in the north-western city of Jolfa since 2000.
Amnesty says she was sentenced to five years in prison, followed by execution, but adds that the Supreme Court has brought forward the execution to 21 December.
The group also highlighted the case of another woman, “Leyla M”, thought to be facing imminent execution for “acts contrary to chastity” in the city of Arak.
Iranian law is extremely specific about how a stoning sentence should be carried out, says Amnesty, ordering that men be buried up to their waists and women up to their chests.
The stones used must be small enough not to kill instantly, it says.
This specificity “leads you to believe that the punishment is designed to maximise suffering”, Amnesty International’s Steve Ballinger told the BBC.
The group says there were documented cases of 108 people being executed in Iran last year – making Iran second only to China in the rate of executions.
