The bill was approved on Sunday by all 247 deputies present in the 290-seat chamber.
The document did not specifically order the government to resume uranium enrichment immediately or to end snap UN inspections of atomic facilities, as some lawmakers had demanded.
But the outline bill called on the authorities to continue work on the nuclear fuel cycle which includes uranium enrichment - a clear rejection of the UN atomic watchdog's demand that Iran halt such activities.
Uranium enrichment can be used both to produce nuclear power and to make atomic bombs.
"The message of this bill is that we will not give in to pressure," parliament Speaker Gholamali Haddadadel said after the bill was approved. "The Iranian nation is determined to use peaceful nuclear technology."
Iran denies US charges it is secretly building nuclear weapons and says it will press ahead with its nuclear programme in order to generate electricity from atomic reactors to meet booming demand.
The European Union has urged Iran to freeze uranium enrichment before the next meeting of the UN's International Atomic Energy Agency (IAEA) on 25 November.
Iran says its nuclear programme
is for generating electricity only
Failure to do so could mean Iran's case being referred to the UN Security Council for possible sanctions.
Political analysts believe the parliamentary debates on the nuclear programme aim to send a message to the outside world that conservatives in Iran could force the government to adopt a tougher line if too much diplomatic pressure were applied on Tehran.
Lawmakers who advocate resuming uranium enrichment said the bill approved on Sunday was too soft.
"We must vote for a bill which puts an end to the [voluntary] suspension of uranium enrichment instead," MP Sayd Abu Talib said.
Iran is not currently enriching uranium. But it is building and assembling enrichment centrifuge parts and has announced plans to convert tonnes of raw uranium ready for enriching.
EU negotiators will meet their Iranian counterparts in Paris on Friday for a third round of discussions on forging a truce over the nuclear issue.
Hoping to persuade Iran to scrap its nuclear fuel cycle activities, the EU is offering Tehran a guaranteed supply of nuclear fuel, help with a light-water nuclear power reactor and a resumption of trade talks.
The EU offered Iran guaranteed
nuclear-fuel supply as incentive
So far Iran has said it is entitled to produce its own nuclear fuel and will not give up that right. "We hope Europe shows more flexibility so that we can reach an agreement," foreign ministry spokesman Hamid Riza Asifi told a weekly news conference on Sunday.
"Europe's commitments should be tangible, concrete, accurate and clear," he added.
In a symbolic move to show popular support for the nuclear programme, students plan to form a human chain around the Iranian Atomic Energy Organisation's buildings in Tehran on Monday.