Abstract: A telescoping extension chute has a first semicircular section with an inlet end for pivotal connection to a main chute on a mixer truck and a pair of tubular tracks attached along upper longitudinal edges. An intermediate section with a semicircular cross-section of larger radius telescopes over the first section and has a pair of tubular tracks attached along upper longitudinal edges which extend through slots formed in the bottom walls of the first section tracks. A third section with a semicircular cross-section of still larger radius telescopes over the intermediate section and has a pair of bars attached along upper longitudinal edges which extend through slots formed in the bottom walls of the intermediate section tracks. Rollers attached to the tracks cooperate to provide relative telescoping movement and a locking mechanism prevents relative movement in any extended position.