He was created a cardinal deacon by Pope Benedict XVI in a consistory on 18 February 2012 and assigned the titular church of Santa Maria Goretti. Grech delivered the opening meditation at the 2013 papal conclave, but his age prevented him from participating as an elector. He warned that the Church was always threatened by disunity: "Between ultra-traditionalist extremists and ultra-progressive extremists, between priests rebelling against obedience and those who don't recognize the signs of the times, there always will be the risk of small schisms that not only damage the church, but go against the will of God." He raised the issue of how the Church hierarchy was handling the sexual abuse crisis: "Today many people are not able to come to believe in Christ because his face is obscured or hidden behind an institution that lacks transparency." When Pope Francis marked the 50th anniversary of the founding of the Augustinianum, he praised Grech for the "grandiose simplicity" his sermons had achieved in his old age.