The divorced women, Helena Paixao, 40, and Teresa Pires, 33, were married in Lisbon before about 30 people.
The lesbians, who have two daughters from previous marriages and have been together for eight years, were also the first gay couple to submit a request to be married back in 2006, which launched the debate on legalising homosexual unions in Portugal, a predominantly Catholic country.
After their request was rejected four years ago, the couple began a long legal process but the rejection was upheld by the constitutional court last July.
Portugal's majority leftist parliament passed the law legalising gay marriages in February. It changed the definition of marriage in the civil code by removing the reference to two people of different sexes.
However, the new law explicitly states married homosexual couples do not have the right to adopt children.
Pope Benedict XVI criticised gay marriage and abortion as "insidious and dangerous threats to the common good" during a visit to Portugal last month.
Portugal follows Belgium, the Netherlands, Spain, Sweden and Norway in allowing same-sex marriages.
SIC: AFP