Abstract: An ignition system for internal combustion engines with spark ignition comprising an ignition coil, a spark plug connected to the secondary winding, an electric supply circuit associated with the primary winding of the coil, where the said circuit includes a semiconductor device controlled by an electronic control unit programmed to produce a charging cycle in the course of which the instantaneous current flowing in the primary winding gradually increases from a minimum value to a maximum value and then returns brusquely to the minimum value. The electronic control unit is programmed to produce a succession of charging cycles during one and the same engine cycle. Each of the said charging cycles is separated from the previous cycle by a time interval (W) of a duration that is either equal to or greater than the duration (DA) of a discharge cycle.