Automated functions and autonomy are increasing in mobile machines. In manual machines, humans have the main responsibility of safety. When level of automation is increased, the automation system needs to take more responsibility. Driverless cars have been leading the development of autonomous ground vehicles due to enormous amount of research. Autonomous mobile machines are operating usually in isolated areas and there is a fleet management system to operate all the mobile machines, whereas driverless cars are operated locally using on-board systems. Examples of autonomous mobile machine systems can be seen in mines and ports. One special risk source of autonomous vehicles is related to perception systems. Outdoor perception sensors are not capable to operate in all environmental conditions. There are also many situations beside or behind a larger object where perception sensors are inadequate to detect persons due to blind spots related to a long detection range. Another specific risk source of autonomous mobile machines is communication. Communication is needed, for example, to control and use area access control system, area status and conditions information, permitted speed and task information, terrain maps and emergency commands. VTT has made a checklist to identify risk sources specific for autonomous mobile machines. The checklist does not describe the risks in detail, but it is intended to be comprehensive in device level. However, there are many kinds of different applications and new technologies are developed continuously. Therefore, risk sources for all kinds of autonomous mobile applications cannot be presented. The checklist gives ideas for risk assessment to identify new risk sources.