Abstract: The present invention provides a wellhead hydraulic drive unit to operate various styles of downhole pumps, which is installed as an integral part of a wellhead thereby eliminating the need for a stuffing box. The wellhead hydraulic drive unit comprises a hollow hydraulic cylinder having a piston positioned therein, a hydraulic fluid supply attached to the hydraulic cylinder for raising the piston within the hydraulic cylinder, a hollow ram slideably received within the inner wall of the hydraulic cylinder and connected to the piston for reciprocation in response to the piston; and a production tube inserted through the ram for enabling well fluid to be discharged from the well.