A self-contained automatic lubricator for automatically dispensing fluent lubricant over a period of time is provided. The lubricator comprises a cylinder having a front wall with a discharge outlet, a rear wall and cylindrical side walls. A piston is movable within the cylinder from a rear position to a forward position. The piston and the side and front walls of the cylinder define a variable volume chamber for containing the lubricant to be dispensed, and a spring for moving the piston from its rear position towards it front position to reduce the volume of the variable volume chamber over a period of time for expelling lubricant through the discharge outlet. The lubricator further comprises a controller including gearing and an escapement mechanism, for controlling the transfer of energy from the spring to the piston and an electrical element controlling operation of the escapement mechanism (12).