A drain cleaning machine with an electronic cable monitoring system is disclosed which comprises a frame supporting a rotatable drum which is driven by a motor through an endless belt. The drum contains a flexible drain cleaning cable which is rotatable with the drum and axially displaceable into and out from the drum, and the frame supports a cable feeding device through which the cable extends and by which the cable is displaced into and out of the drum. An electronic cable monitoring system is configured to assess an amount of cable payed out from and retracted into the drum. A process determines an amount and direction of relative movement between a rotatable drum and a cable follower member and generates a signal representative of an amount of cable payed out or retracted into the drum.