The lamp is provided for the purpose of replacing the conventional lamps in public lighting luminaires, said lamp comprising a succession of dissipating modules (3) which are fixed on a base (1) and are configured to fix, on the periphery thereof, at least one card (9) carrying a plurality of LEDs (10). The lamp is characterized in that the dissipating modules (3) are configured to assemble the contiguous modules and to simultaneously fix the card of LEDs; the different cooling modules (3) being separated from one another in order to allow the flow of air therebetween. The cards (9) of LEDs (10) have an elongated configuration. The dissipating modules (3) have a configuration formed by sectors separated from one another in order to provide a very wide contact surface which facilitates the heat dissipation.