The violoncello, or more informally referred to as "cello," is pitched one octave below the viola. Unlike the violin and viola, which are held under the chin of the performer, the cellist holds the instrument between their legs. An adjustable peg, or endpin, on the bottom of the instrument is used to support the instrument at the desired performance height for the performer.

The cello has a very wide range and may be written in bass clef, tenor clef, or treble clef. Proficiency in reading the tenor clef may be limited for new composers and orchestrators, but writing higher passages in the tenor clef should not be avoided. Cellists are very used to reading the clef and the use of the clef is preferred to reading several ledger lines. It is best, however, to switch to appropriate clefs for longer passages instead of just for one or two notes.

Natural harmonics up to the 7th harmonic (8th partical) are displayed, but as already stated, natural harmonics become easier on larger instruments. For this reason, works written for professional players may go up to the 12th partial, but for younger musicians, it is wise to not go beyond the 8th partial. Artificial harmonics are also very effective; however, cellists with smaller hands will have difficulty with harmonics that require them to lightly touch a perfect 5th above the stopped notes especially in the lower positions.

Due to the resonance of the cello, pizzicato, sul tasto, and sul ponticello are extremely effective. These techniques have a wide dynamic range and provide additional colors for the cello.

The cello is perhaps the most timbral diverse instrument of the string family. The low C string on the cello is often described as "heavy" and "rich." The two lowest strings can deliver a lot of power, but in an orchestra setting, can disappear if written too softly. Often times, the cello section doubles the contrabass, especially in earlier orchestral music. It can also provide support for inner harmonic notes and be an accompaniment instrument since it blends well with other instruments. The cello, however, is also a powerful and effective melodic instrument. It can easily double the violin and viola sections, or be in the foreground by itself. The upper register can be incredibly expressive. An excellent example of this can be found in the 5th movement Messian's Quartet for the End of Time, "Praise to the Eternity of Jesus" here.