The article deals with the concept of professional competence of the Biology teacher at profession-oriented school. On the basis of the analysis of educational and professional programs of Biology teacher training at the institutions of higher education in Ukraine, such components as integral, general and professional are distinguished in the structure of their professional competence. At the intersection of general competences (provide the opportunity for professional pedagogical activity) and professional (reflect the features of the field of Biology, modern methods and teaching Biology techniques), specialized professional competence of the Biology teacher at upper secondary school is formed. According to the author, it is a dynamic integrated system of theoretical knowledge, practical skills, emotions, motives, attitudes, values and experience of the individual, which provides successful implementation of daily professional educational activities in terms of profile organization of training. Motivational-value, cognitive, activity and personality-reflexive components are distinguished, criteria and indicators of their formation are determined in the structure of the professional competence of the teacher at the specialized school. The survey results of Biology teachers of Zhytomyr region, students of bachelor's and master's degrees of higher education, different universities of Ukraine are presented in the paper. The study confirmed the positive perception of the specialized education introduction by the pedagogical community and the lack of internal motivation and willingness of teachers to implement it. The results of the experiment ascertaining stage demonstrated the necessity for continuous professional training of Biology teachers to work in a specialized upper secondary school; introduction of changes in the system of teacher training in institutions of higher and postgraduate pedagogical education. Study of the cognitive and operational activity components of the professional competence of bachelors, masters, and Biology teachers revealed that among all categories of respondents, specialized knowledge about the organization of specialized education in upper secondary school is the worst formed; realization of scientific, research, career guidance work; methods of differentiated teaching in classes of various specializations and profiles. It is difficult to work with creative, gifted students, organize their participation in competitions, contests, research projects. Students, according to self-assessment, consider their own biological, research, methodological knowledge and skills to be formed insufficiently. Moreover, at the levemaster’s degreel quantity of individuals with sufficient and high level of this component of professional competence increases. Many teachers find it difficult to preserve and maintain their own health; the use of innovative pedagogical techniques, especially information and computer technologies.