The present invention relates to an illumination device where a number of light sources are arranged on a heat sink and adapted to emit light in substantially the same direction. The heat sink comprises a first cooling plate and a second cooling plate. A first part of the light sources are arranged on the first cooling plate and a second part of the light sources are arranged on the second cooling plate. The first and second cooling plates are separated by a distance and a flow channel is defined there between. The flow channel allows cooling fluid to flow between the first cooling plate and the second cooling plate whereby the light sources can be cooled by the cooling fluid. The heat sink comprises further a number of light passages allowing light to propagate from the second cooling plate, towards the first cooling plate and through the first cooling plate.