Ruffo's repertoire included most of the major baritone roles in French and Italian opera, including among others Rigoletto, Di Luna, Amonasro, Germont, Tonio, Rossini's Figaro, Valentin, Iago, Carlo (in both Ernani and La forza del destino), Nabucco, Vasco, Don Giovanni, Barnaba, Scarpia, Marcello, and Renato in Un ballo in maschera.
He was also renowned for his interpretations of several baritone parts in operas that are largely forgotten today, namely, the title roles in Ambroise Thomas's Hamlet and Franchetti's Cristoforo Colombo plus Cascart in Leoncavallo's Zazà and Neri in Giordano's La cena delle beffe.

Like his tenor contemporary Enrico Caruso, Ruffo was said to embody a new style of singing in which power, declamatory force and a rich, chesty tone eclipsed the previous generation's emphasis on vocal grace, flexibility and technical finesse.
Consequently, some conservative commentators compared Ruffo unfavorably with his elegant Italian predecessor Mattia Battistini, who was a master of bel canto and the possessor of a leaner, more silvery timbre than Ruffo's.
However, according to modern-day critics like John Steane and Michael Scott, the difference between the two great baritones was not quite as clear cut as some have suggested in the past, because both Battistini and Ruffo displayed exceptional vocal agility and control plus the ability to sustain a long legato line.
Both of them also favored a virile interpretive style and even shared a teacher in Venceslao Persichini.

Writing in the Gramophone magazine in 1928, the often acerbic British critic and future record producer, Walter Legge, lauded Ruffo's singing, recalling a recital that he had heard the baritone give six years earlier in London.
Legge said that: "From the his first phrase the audience was vanquished by the overwhelming beauty of his voice—manly, broad, sympathetic, of unsurpassed richness.
Such ease of production, such abundance of ringing high Gs!
But more: Ruffo's infinite subtlety, variety of tone-colour, interpretive insight and sincerity, his magnificent control, stupendous breathing powers, and impeccable phrasing stamped him as a genius."

Ruffo was a prolific recording artist.
He made more than 130 78-rpm records, both acoustic and electric, first for Pathé Frères in Paris in 1904, and then exclusively for the Italian affiliate of Grammophone & Typewriter Company (later known as La Voce Del Padrone/Italian HMV) beginning in 1906.
Then upon arriving in the United States in 1912 he began his long association with the Victor Talking Machine Company which concluded in 1929.
As was the case with Caruso, Ruffo's voice recorded remarkably well; it was so rich and resonant that even on the primitive acoustic recording process, much glory remains to be heard.
 He continued recording into the electrical recording era after 1925, but at far as one is able to judge (many titles remain unpublished) most of those later published records caught him past his prime, with what Steane calls a "hollowness" now evident in his mid-range.
However, the unpublished Victor electrics, and some unpublished sides made even later, in London in 1933 are more than touching "beaux restes", with (strangely, compared with the published electrical recordings) a great deal of voice, technique and charm still surviving to this late date.

As Steane and Pleasants mention, Ruffo made records at his peak of two arias which stand-out as exemplars of his voice and style.
The first example is the Brindisi from Hamlet (made in 1907 and remade in 1911), the cadenza of which demonstrates his astounding élan and breath control.
The second is the unaccompanied "All'erta, marinar!"
from Meyerbeer's L'Africaine, which exhibits the resonance, power and brilliance of his upper register.
For examples of his vocal agility, his early discs of "Largo al factotum" from Il barbiere di Siviglia stand out.
Other discs of arias singled out for praise by Pleasants, Steane and/or Scott include Ruffo's acoustic Victor recordings of the following arias: "Pari siamo", "Urna fatale", "Credo in un Dio cru
Ruffo's repertoire included most of the major baritone roles in French and Italian opera, including among others Rigoletto, Di Luna, Amonasro, Germont, Tonio, Rossini's Figaro, Valentin, Iago, Carlo (in both Ernani and La forza del destino), Nabucco, Vasco, Don Giovanni, Barnaba, Scarpia, Marcello, and Renato in Un ballo in maschera. He was also renowned for his interpretations of several baritone parts in operas that are largely forgotten today, namely, the title roles in Ambroise Thomas's Hamlet and Franchetti's Cristoforo Colombo plus Cascart in Leoncavallo's Zazà and Neri in Giordano's La cena delle beffe.
Like his tenor contemporary Enrico Caruso, Ruffo was said to embody a new style of singing in which power, declamatory force and a rich, chesty tone eclipsed the previous generation's emphasis on vocal grace, flexibility and technical finesse. Consequently, some conservative commentators compared Ruffo unfavorably with his elegant Italian predecessor Mattia Battistini, who was a master of bel canto and the possessor of a leaner, more silvery timbre than Ruffo's. However, according to modern-day critics like John Steane and Michael Scott, the difference between the two great baritones was not quite as clear cut as some have suggested in the past, because both Battistini and Ruffo displayed exceptional vocal agility and control plus the ability to sustain a long legato line. Both of them also favored a virile interpretive style and even shared a teacher in Venceslao Persichini.
Writing in the Gramophone magazine in 1928, the often acerbic British critic and future record producer, Walter Legge, lauded Ruffo's singing, recalling a recital that he had heard the baritone give six years earlier in London. Legge said that: "From the his first phrase the audience was vanquished by the overwhelming beauty of his voice—manly, broad, sympathetic, of unsurpassed richness. Such ease of production, such abundance of ringing high Gs! But more: Ruffo's infinite subtlety, variety of tone-colour, interpretive insight and sincerity, his magnificent control, stupendous breathing powers, and impeccable phrasing stamped him as a genius."
Ruffo was a prolific recording artist. He made more than 130 78-rpm records, both acoustic and electric, first for Pathé Frères in Paris in 1904, and then exclusively for the Italian affiliate of Grammophone & Typewriter Company (later known as La Voce Del Padrone/Italian HMV) beginning in 1906. Then upon arriving in the United States in 1912 he began his long association with the Victor Talking Machine Company which concluded in 1929. As was the case with Caruso, Ruffo's voice recorded remarkably well; it was so rich and resonant that even on the primitive acoustic recording process, much glory remains to be heard.  He continued recording into the electrical recording era after 1925, but at far as one is able to judge (many titles remain unpublished) most of those later published records caught him past his prime, with what Steane calls a "hollowness" now evident in his mid-range. However, the unpublished Victor electrics, and some unpublished sides made even later, in London in 1933 are more than touching "beaux restes", with (strangely, compared with the published electrical recordings) a great deal of voice, technique and charm still surviving to this late date. 
As Steane and Pleasants mention, Ruffo made records at his peak of two arias which stand-out as exemplars of his voice and style. The first example is the Brindisi from Hamlet (made in 1907 and remade in 1911), the cadenza of which demonstrates his astounding élan and breath control. The second is the unaccompanied "All'erta, marinar!" from Meyerbeer's L'Africaine, which exhibits the resonance, power and brilliance of his upper register. For examples of his vocal agility, his early discs of "Largo al factotum" from Il barbiere di Siviglia stand out. Other discs of arias singled out for praise by Pleasants, Steane and/or Scott include Ruffo's acoustic Victor recordings of the following arias: "Pari siamo", "Urna fatale", "Credo in un Dio cru
Titta Ruffo