It has been 17 years since Bangladesh became the 10th nation to be allowed to compete in the five-day format of the game, but a vote was carried out by ICC members to decide whether two more international sides could become full members.
The results revealed that the panel had unanimously decided to give both nations the green light to step up from the one-day arena.
Ireland have been on the international radar since 2007 when they reached the Super 8 at the World Cup, and they have a record of seven wins from 22 matches in the history of the tournament.
They have also featured at the last five Twenty20 World Cups, but have only progressed past the group stages on one occasion in five attempts.
As for Afghanistan, they made their first appearance at the 50-over World Cup in 2015, while they claimed a victory over West Indies at the 2016 Twenty20 World Cup.