Abstract: An ignition system for at least one spark plug of an internal combustion engine includes an ignition coil having a secondary winding connected to the plug, a control commutator device controlling the flow of current in the primary winding of the ignition coil, a device for monitoring the intensity of the current flowing in the primary winding and electrical sensors which provide signals indicative of the operating conditions of the engine. A control unit is provided with memory devices in which are stored data indicative of predetermined final values for the current in the primary winding of the ignition coil associated with various operating conditions of the engine. The control unit is also arranged to pilot the commutator device so that each time a spark needs to be generated the flow of current in the primary winding of the ignition coil is stopped when the magnitude of current has reached the final value which is associated in the memory device with the prevailing operating conditions of the engine.