The article presents the method for the support of diagnostic processes with the use of an original computer system in which augmented reality is applied. The proposed solution constitutes a significant step towards improving actions directed at the assessment of the technical condition of complex technical devices. The research problem presented in the article was defined through the determination of the scope of diagnostic tasks which the personnel may find difficult in certain technical conditions. The research method consisted in the selection of a technology facilitating effective execution of diagnostics of complex technical devices. In the developed solution diagnostic processes are executed via the visual presentation of the following: the location of the components of the device, the diagnostic tasks, the descriptive hints, the measurement values, the location of the measurement points, and the 3D models of the components