Castrati played heroic male leads from the mid-17th to late 18th century when the bel canto was the rage in Europe.
Farinelli, born Carlo Broschi in 1705, was the most famous of all, in a career lasting from 1720 to 1737.
Scientists at Bologna University are to study the remains, recovered yesterday from the city's Certosa cemetery.
An acoustics expert is eager to find remains of the vocal chords and larynx to discover what gave castrati such extraordinary vocal range and power.
The last castrato, the Sistine Chapel chorister Alessandro Moreschi, made recordings in 1902 and 1904, though on the dated gramophone records his voice has been described as "Pavarotti on helium".