An important investigation of St. Anthony's mortal remains was conducted on 6 January 1981, on the occasion of the 750th anniversary of the Saint's death. Religious and scientific commissions, both nominated by the Holy See, opened the tomb and examined the contents.

Once the green marble tombstone had been removed, a large wooden chest was found wrapped in cloth.

This chest contained another smaller wooden chest, inside which various items, wrapped in precious cloth and labelled, were found in three compartments.They included the skeleton, apart from the chin, the left forearm and other minor bones, which for centuries had been preserved in special reliquaries.
The other contents included St. Anthony's woollen habit; a stone with the date of his death and another one with the date of the recognition and transposition of 1263 and the "massa corporis", his ashes.