Troubleshooting is often a time-consuming and difficult activity. The question of how the training of novice technicians can be improved was the starting point of the research described in this article. A cognitive task analysis was carried out consisting of two preliminary observational studies on troubleshooting in naturalistic settings, combined with an interpretation of the data obtained in the context of the existing literature. On the basis of this cognitive task analysis, a new method for the training of troubleshooting was developed (structured troubleshooting), which combines a domain-independent strategy for troubleshooting with a context-dependent, multiple-level, functional decomposition of systems. This method has been systematically evaluated for its use in training: The results show that technicians trained in structured troubleshooting solve twice as many malfunctions, in less time, than those trained in the traditional way. Moreover, structured troubleshooting can be taught in less time than can traditional troubleshooting. Finally, technicians learn to troubleshoot in an explicit and uniform way. These advantages of structured troubleshooting ultimately lead to a reduction in training and troubleshooting costs.