In this report we describe how laser-based sensors can be used in surveillance systems, either independently or in conjunction with other types of sensors. Laser sensors are considered as active sensors (emitting energy), unlike, e.g. video or infrared cameras. The advantage of a passive sensor is that it is harder to detect than an active sensor. As an active sensor sends out energy, it is also easier to detect, and thus easier to put out of action. However, active sensors can provide other benefits, such as better accuracy and longer range, which justifies their use. With a laser sensor, the geometry and velocity of an object can be measured. With laser sensors, the ability of a surveillance system can be improved by supplying range information, which adds a new dimension and can help to more easily distinguish the different persons or vehicles from each other. Speed information, which can facilitate discrimination of persons or vehicles from the background, can also be obtained. The surveillance system can also be made more robust (more jamming resistant and harder to deceive) and improved capability in darkness and poor visibility. The technical descriptions of systems on the market should be viewed as examples; it is not a comprehensive list of operational systems. The selection has to some extent been guided by the scenarios discussed in the project on surveillance systems, namely, a camp in an urban area where people and vehicles can move legitimately outside the compound, without being regarded as antagonistic threats. Several ways to use laser sensors are described in the report; besides distance measurement they can be used as a laser barrier or for 3D imaging, counting people, face detection and remote listening.