A pilgrimage from the saint's birthplace will precede the solemn celebration of the Mass.
Padre Pio was ordained in a chapel at the Cathedral of Benevento, Italy on Aug. 10, 1910 at the age of 23.
This year's celebration for the century milestone will be held on the same day, but this year Archbishop of Benevento Andrea Mugione will preside over Mass in the courtyard of the archbishop's residence.
The Italian Bishops' news service SIR announced the Mass to remember the unique event.
On that day, young Francesco Forgione, already a Capuchin for more than seven years, was given a dispensation by the local bishop from the minimum age requirement for priestly ordination, 24 years-old, because of a serious illness.
Despite his health problems he, his mother, brother and parish priest walked to Benevento so he could receive Holy Orders.
The diocese's current vicar general, Msgr. Pompilio Cristino announced that for the 100th anniversary, "To relive the trip made that morning by Fr. Pio ... a pilgrimage will depart on foot from the parish of Pietrelcina at 5 a.m."
The route covers approximately eight miles.
Msgr. Cristino said that the the faithful will also have the opportunity to obtain a plenary indulgence during the Eucharistic celebration.
SIC: CNA