The research aims to identify conditions for the formation of professional ICT-competence when learning programming and to experimentally verify their effectiveness. This is especially relevant in the context of the changing requirements for IT-experts and computer science teachers. The analysis of the current state and problems of professional training of IT-experts and computer science teachers is based on: (1) scientific works of recognized experts in the field of teaching computer sciences and, in particular, programming; (2) current orders of the Government of the Russian Federation on the approval of the teacher's professional standard and the program "Digital Economics of the Russian Federation"; (3) educational programs in relevant areas; (4) the authors' personal experience reflected in the relevant research articles. In the research, a number of scientific methods were used. To identify the conditions for the effective formation of professional ICT-competence, a general scientific analysis method was applied. To verify the identified factors in specially created and controlled conditions, a pedagogical experiment was conducted. The research was carried out in several phases. The first phase included a general analysis of programming teaching systems and the formation of professional ICT-competence in the framework of training future informatics teachers and IT-experts in higher education institutions. During the second phase, the conditions for the effective formation of professional ICT-competence in the context of teaching programming were identified. The first condition is the possibility of constructing a process of teaching programming on the basis of the problem-semiotic approach. The second condition is the use of STEM-technology. The third condition is the use of specialized video content in accordance with the trends of modern IT-technologies (the flipped classroom concept). At the third phase of the research, a qualitative assessment of the effectiveness of the selected conditions was made. For this, an approach was applied in which the main measurement criterion is the characteristic of advancing to higher levels of professional ICT-competence, which implies the formation of special competencies decomposed into knowledge, abilities, and skills. This approach allowed formalizing the assessment process and proving the hypothesis about the influence of the selected conditions on the effectiveness of the formation of professional ICT-competence using statistical measurement (a chi-square test). Thus, the research allows considering the application of the problem-semiotic approach, modern IT-technologies, and exercises within the framework of STEM-education as effective conditions for the formation of professional ICT-competence when teaching programming to future computer science teachers and IT-experts.