The proposal was brought forward by bishops from across the pan-Amazon region as a way to combat the shortage of priests in the area which has meant some of the most isolated Amazonian communities go months without a proper Mass.
The majority of 180 bishops, including 113 from nine Amazonian nations, also called for the Vatican to reconsider ordaining women as deacons.
Those in favour of the move said “it is urgent for the church in the Amazon to promote and confer ministries for men and women in an equitable manner”.
The “progressive” proposals were outlined in a document approved on Saturday at the end of the synod on the Amazon, which discussed methods to save the rainforest and better minister to its indigenous people.
The proposal on ordaining married priests was the most controversial paragraph, but received the mandatory majority 128-41.
If approved, the historic proposal would overturn centuries of Roman Catholic tradition.
The Catholic Church, which contains nearly two dozen different rites, already permits married priests in Eastern Rite churches and when married Anglican priests have converted.
But if Pope Francis accepts the new proposal, it would mark a first for the Latin Rite church in a millennium.
The celibate priesthood has been a tradition of the Latin Rite Catholic Church since the 11th century, introduced partly for financial reasons to ensure that priests’ assets went to the church, not to heirs.
Francis has long said he appreciates the discipline and the gift of celibacy, but that it can change, given that it is discipline and tradition, not doctrine.
The second most contested proposal was ordaining women as deacons, a title that would allow them to preach and celebrating weddings and baptisms, but not consecrate the Eucharist.
The bishops didn’t come straight out and call for women deacons, but rather for the Vatican’s 2016 commission on the female diaconate to hear from the synod about “our experiences and reflections” and come to a decision.
The paragraph was passed 137-30.
The 2016 commission delivered its report to Pope Francis but the results were never released and the pontiff said commission members failed to come to an agreement.
Francis said on Saturday that he would reopen the work of the commission.
He also said he planned to take the bishops’ overall recommendations and prepare a document of his own before the end of the year that will determine whether married Catholic priests should be allowed in the Amazon.
Some conservatives and traditionalists have argued that any papal opening to married priests or women deacons would lead the church to destruction.
A group of ultra-conservatives vented their outrage by stealing three indigenous statues featuring a naked pregnant woman from a Vatican-area church and throwing them to into the Tiber River.
The statues, which conservatives said were pagan idols, were recovered undamaged by Italian police.
Pope Francis has since apologised for the incident.
“This happened in Rome, and as bishop of the diocese I ask the forgiveness of those offended by this gesture,” he said.