The FMPR was formed in 1960s by radical union activists. It currently has 32,000 members, making it one of the largest unions in Puerto Rico. The FMPR has recently disaffiliated from the American Federation of Teachers. A referendum within the union decided on a majority vote to disaffiliate with the AFT and the AFL-CIO. The details of the referendum were published on their website and the votes were counted by the teachers themselves according to official reports. The conflict between the two unions remained in limbo through January 2005, when hundreds of FMPR officers opposed to disaffiliation formally asked AFT to investigate the disaffiliation vote and the governing practices of President Feliciano. Though the AFT investigation alleged numerous violations of the democratic rights of FMPR members, the whole matter of who controlled the FMPR wound up in court in Puerto Rico. FMPR prevailed in the court proceedings.
In April 2003 some of the union leadership including the president of the union were involved in violent protests which resulted in arrests and jail time for members of the union.
On February 21, 2008, the FMPR officially declared a strike.
Exactly nine days after it began, the FMPR declared the strike over.