The Archbishop of Tuam said the contents of the mother and baby home report are a cause for “shame”.
Michael Neary said the Church was intended to bring “hope and healing”, but it brought “harm and hurt” for many women and children.
He added: “Many were left broken, betrayed and disillusioned.
“For them, and all of us, these revelations seriously tarnished the image of the Church.”
He said the joy which is associated with the birth of a new baby was “clouded with darkness and gloom”.
“This was a time when single, pregnant women and their children were labelled as ‘unmarried mothers’ and ‘illegitimate’, and then judged, stigmatised and ostracised by their own families, by their communities, and the Church,” the Archbishop added.
He said this was wrong and very sad.
He added that the Church failed in its responsibility to love and cherish those who were diminished.
“What this report makes clear to me is that when the Church is not serving with compassion, it is failing. For that I am genuinely sorry,” he added.
“As a Church leader, I apologise unreservedly.”
The Tuam Home was owned by Galway County Council and operated by the Bon Secours Sisters.
Archbishop Neary said that everything in the Diocesan archives relating to the home has been shared with the commission, but added that the archive does not hold any information relating to the living conditions.
He said its archives do not give any insight into the “helplessness and suffering” of the mothers who were separated from their children.
He added that he was “horrified” to learn of the discovery of human remains at the Tuam site through the commission’s interim report in March 2017.
“These discoveries underline the enormous suffering and pain for the little ones and their mothers,” he said.
He added: “Furthermore, the disparity which continues to exist between the Register of Deaths, and the absence of burial location records, is a critical aspect of this sad story which remains unreconciled. This disparity is a matter of great public concern.
“The burial pattern in the home in Tuam, more than any other single occurrence, has, understandably, caused the most outrage.
“While the report makes for difficult reading, every step towards uncovering the complete truth regarding the burial pattern is welcome.
“In this way, as a society, we can take appropriate steps to heal the wounds caused, and we will be enabled to move forward together.”
