A cooking grill includes a container defining a combustion area and a cooking surface over the combustion area. The grill features a pellet burner unit disposed within the container under the cooking surface and a pellet feeding device arranged to feed pellets into the burner unit. The burner unit comprises a trough into which the pellets are fed. The trough is mounted in a movable support which can be pulled out from within the container. The feeding device includes a removable cartridge for containing pellets and a receptacle for receiving the cartridge inserted thereon so that the cartridge supplies pellets for transfer to the pellet burner unit. In addition, a gas burner system is arranged in the container adjacent to the pellet burner unit so as to apply heat from the gas burner system to the cooking surface in addition to or as an alternative to the pellet burner unit.