The Rev. Paolo Padrini, a consultant with the Vatican's Pontifical Council for Social Communications, said Friday the free application will be launched in July in English, French, Spanish, Italian and Latin.
Two years ago, Padrini developed the iBreviary, an application that brought the book of daily prayers used by priests onto iPhones. To date, some 200,000 people have downloaded the application, he said.
The iPad application is similar but also contains the complete missal - containing all that is said and sung during Mass throughout the liturgical year. Upgrades are expected to feature audio as well as commentaries and suggestions for homilies as well as musical accompaniment, he said.
"Paper books will never disappear," he said in a phone interview from his home parish in Tortona, in Italy's northern Piemonte region. But at the same time "we shouldn't be scandalized that on altars there are these instruments in support of prayer."
Padrini, 36, said he expected priests who have to travel a lot for work would find the application most useful, noting that he recently had to celebrate Mass in a small parish where the missal was "a small book, a bit dirty, old."
"If I had had my iPad with me, it would've been better than this old, tiny book," he said.
Pope Benedict XVI, a classical music lover who was reportedly given an iPod in 2006, has sought to reach out to young people through new media: the Vatican has a regularly updated presence on You Tube and Facebook. Based on the success of the iBreviary, Padrini was recruited by the Vatican to oversee its youth outreach program in the new media, http://www.pope2you.net .
He stressed that the iPad application, like the iBreviary, was launched at his own instigation and with his own money and is not an official Vatican initiative. Vatican officials have previously praised the iBreviary as a novel way of evangelizing.