Barcelona officially withdrew from the European Super League project last week before submitting its application for re-admission to the EFC, formerly known as the European Club Association, until the body was rebranded in October.
The EFC, which represents over 800 clubs across Europe, shapes key decisions on competitions, match calendars, financial frameworks, transfer regulations and commercial policy.
Barcelona said EFC chairman and Paris St Germain president Nasser Al-Khelaifi personally presented Barcelona's membership application to the board.
"EFC has expressed its satisfaction and honour in welcoming FC Barcelona back as an Ordinary Member and has conveyed its willingness to work closely with the club to define the next steps and to specify its involvement within the organisation in this new stage," the club said.
"FC Barcelona views this decision very positively and reaffirms its commitment to working together with fellow European clubs for the benefit of football, its competitions and its supporters."
Barcelona's withdrawal from the Super League left Real Madrid as the sole remaining advocate for the breakaway competition.
However, Real reached an agreement with UEFA earlier this week to put their bitter legal feud to bed.
Barcelona face a trip to Girona on Monday - follow the game with Flashscore.