Abstract: A trencher attachment for a hydraulic excavator of the truck mounted type enables the excavator to be effectively used in performing trenching functions relative to the construction and maintenance of various underground installations. The trencher attachment and a trencher carried thereby on the free end of a telescopic boom of the excavator can be moved toward and away from the excavator, lifted and lowered, tilted and swung to any desired location where the trencher may be actuated by remote control from the excavator. The trencher attachment thereby enables a trenching operation to be performed in locations heretofore inaccessible to trenchers presently known in the art.