Entering teaching profession is considered as the most determining stage in a teacher’s professional life. The aim of this research is to explore opinions of novice teachers in Latvia about the role of mentoring in their professional socialization. The following research questions were defined: (1) what difficulties novice teachers faced during their in-service experience? (2) what support novice teachers needed when they started teaching? (3) what the role of mentoring in teachers’ professional socialization is? Qualitative research design was developed for the research. Empirical data were obtained during the focus group discussion with ten teachers representing Council of young teachers (in age below 35) of the Latvian Trade Union of Education and Science Employees, nine semi-structured interviews with novice teachers, and interview with a mentor. Novice teachers face teaching reality which often differs from perceptions about the profession developed during the studies at university. The research shows that teachers from the sample faced following challenges during their first years of in-service: establishing teacher’s authority and self-positioning as a teacher, time management, problems with discipline in a classroom, lack of skills to develop curriculum and lesson plans, difficulties in communication with parents. During socialization novice teachers learned their responsibilities and acquired specific knowledge; appropriate support such as mentoring reduced level of stress and uncertainty while novice teachers adapted to school during the period of transition from pre-service period to in-service period. In relation to mentoring, novice teachers expected that a mentor would introduce them to school traditions and internal rules and would advise on discipline in a classroom as well as would help to develop curriculum. Policy makers should focus on teachers’ support guidelines at national level, which would allow schools to ensure the most appropriate environment for novice teachers so that they would like to continue their careers in teaching profession. Key words: mentoring, novice teachers, professional socialization, teacher retention, teaching profession.