An illuminating device for vehicles with a housing in which an optical unit with a light source and an optical unit with a reflector and a hologram element are arranged to create a specified light diffusion. The hologram element runs at a right angle to a main radiation direction (H) in front of the illuminating device. The reflector is designed to be a deflecting reflector to deflect the light emitted at an obtuse angle (α) in the direction of the hologram element. The deflecting reflector is arranged outside of a horizontal plane that crosses one of the glare edges of the hologram element. The deflecting reflector is designed as a prism reflector that has a multitude of prism elements arranged in columns and/or rows.