The blue Skoda Rapid will take families from emergency housing in the Dublin area to longer-term accommodation arranged for them by Crosscare, a social care agency in the Irish capital run by the Catholic Church.
A decision of the future of the now famous five-door car was taken by Diarmuid Martin, the Roman Catholic Archbishop of Dublin.
Bosses say the vehicle will be in daily use but the registration plate 'SCV 1' must be changed as it currently stands for Stato della Citta del Vaticano - or Vatican City.
The pope spent two days in Ireland at the weekend as part of the World Meeting of Families Congress which is held every three years.
Speaking at the event, director of Crosscare services, Conor Hickey, said homelessness has become increasingly prevalent in Dublin during recent years.
He said it was affecting "people very much like you or I who, because of economic factors beyond their control, have found themselves in a housing market where there are no available houses".
Fifty families at any one time use The Hub - an over-subscribed temporary accommodation site operated by Crosscare as it tries to move families on to longer-term housing.
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