Abstract: A laser warning device for registering laser radiation from e.g. laser range finders or laser designators and providing a warning signal to make clear to the illuminated person that laser illumination has occurred or continues and establish the direction of incidence. A position sensitive detector or a position sensitive detector arrangement includes a detector surface that is protected from radiation that falls directly onto it, and a reflector. The reflector is designed to reflect towards the detector surface, while focusing towards the line of intersection between the detector surface and a plane that is perpendicular to the surface and in which the direction of incidence for the incoming radiation lies, the radiation that falls on the laser warning device and is parallel to the plane of the detector surface. The latter is defined as diverging not more than .+-.30.degree. from the plane. Further, the radiation may come from an arbitrary angle within the detector plane, up to 360.degree..