Alabama thus joins, at least temporarily, the other 36 states where gays may legally marry.
In a 7-2 ruling, the judges rejected a request by Alabama Attorney General Luther Strange to block gay marriage in the traditionally conservative state.
Federal Judge Callie Granade in January revoked the prevailing prohibition in Alabama on gay marriage, ruling that such a ban was unconstitutional, and starting Monday gays in the state may apply for marriage licences.
After the court’s ruling and despite the fact that Alabama Supreme Court Chief Justice Roy Moore Sunday ordered state judges not to issue marriage licences to gay couples, several homosexual couples requested and obtained them early Monday morning, media reports said.
The US Supreme Court announced in January that during its current session, which ends in June, it will consider whether the 50 US states must allow same-sex marriages.
In a recent interview on YouTube, US President Barack Obama said he was certain that the Supreme Court this year would legalise gay marriage nationwide.
Obama is the first president in US history to publicly express his support for same-sex marriage.