The Constitutional Court ruled last week that common-law partners are eligible for death benefits.
In its decision, the justices struck down a 2007 provision in the Social Security Law that made such partners eligible only if they had children. The court said the rule was "unreasonable" and went against the Spanish Constitution.
The case arose after a plaintiff identified as J. M. d F. filed a lawsuit in Barcelona after his same-sex partner died in 2008. They had been living together since 1982.
The 2007 amendment to the Social Security Law did not affect all those common-law partners whose deaths occurred before the law was passed.
"The requisite of having children in common is very difficult or almost impossible in the case of same-sex partners," the court ruled.
Justice Francisco Pérez de los Cobos cast a dissenting vote, explaining that he believed the regulation was necessary due to the fact that social security funds are being depleted.