The transition of Russian industry to the sixth technological mode and the change of technological paradigms have created a mismatch between expectations and opportunities for modernisation of our industry in accordance with modern requirements. One of the most important factors that can mitigate this discrepancy is the production and reproduction of a sufficient number of highly professional engineers capable of meeting modern requirements. In this regard, it seems important and relevant to study such a concept as professionalism, specifying it for engineering activity. This study was conducted by the Sector of Sociology of Professions and Professional Groups of the Institute of Sociology (Federal Center of Theoretical and Applied Sociology, Russian Academy of Sciences) on the basis of secondary analysis of empirical data from the study of various aspects of the specificity of some professional groups, conducted by the same research staff during 2019-2023. The study was conducted on the basis of a qualitative strategy. Qualitative-quantitative content analysis was used as the main method of data analysis. The aim of our research was to find out the opinion of Russian engineers, who acted as experts, about the qualitative indicators of professionalism in engineering activities. As a result of the data analysis, the concept of professionalism in relation to engineering activity was specified: a meaningful set of qualitative attributes of an engineer-professional, important from the experts' point of view for a good professional, was identified, and a hierarchy of these indicators was constructed. It was found out that, apart from having standard professional knowledge, skills and abilities, experts consider it very important to have certain moral, moral and personal qualities of an engineer-professional. In this regard, it was recommended to the higher technical institutions of the Russian Federation to pay special attention to the educational work among students during the educational process.